dr Njemuwa Njoku Nwaji

Zakład Teorii Ośrodków Ciągłych i Nanostruktur (ZTOCiN)
Zespół Badawczy Nanomateriałów do Zastosowań w Elektronice i Biomedycynie (ZeBNZEiB)
stanowisko: adiunkt
telefon: (+48) 22 826 12 81 wew.: 210
pokój: 209
e-mail: nnwaji

Ostatnie publikacje
1.Nwaji N., Hyojin K., Birhanu Bayissa G., Osial M., Vapaavuori J., Lee J., Giersig M., A Stable Perovskite Sensitized Photonic Crystal P, ChemSusChem, ISSN: 1864-5631, DOI: 10.1002/cssc.202400395, pp.2-9, 2024

Streszczenie:

The slow photon effect in inverse opal photonic crystals
represents a promising approach to manipulate the interactions
between light and matter through the design of material
structures. This study introduces a novel ordered inverse opal
photonic crystal (IOPC) sensitized with perovskite quantum dots
(PQDs), demonstrating its efficacy for efficient visible-lightdriven
H2 generation via water splitting. The rational structural
design contributes to enhanced light harvesting. The sensitization
of the IOPC with PQDs improves optical response performance
and enhances photocatalytic H2 generation under visible
light irradiation compared to the IOPC alone. The designed
photoanode exhibits a photocurrent density of 3.42 mAcm

Słowa kluczowe:

Hydrogen production, inverse opals, perovskite, quantum dots, photocatalysts, photonic crystals

Afiliacje autorów:

Nwaji N.-IPPT PAN
Hyojin K.-other affiliation
Birhanu Bayissa G.-other affiliation
Osial M.-IPPT PAN
Vapaavuori J.-other affiliation
Lee J.-Lexington High School (US)
Giersig M.-IPPT PAN
140p.
2.Nwaji N., Juyong G., My‐Chi N., Huu‐Quang N., Hyojin K., Youngeun C., Youngmi K., Hongxia C., Jaebeom L., Emerging potentials of Fe-based nanomaterials for chiral sensing and imaging, Medicinal Research Review, ISSN: 1098-1128, DOI: 10.1002/med.22003, Vol.44, pp.897-918, 2024

Streszczenie:

Fe-based nanostructures have possessed promising properties that make it suitable for chiral sensing and imaging applications owing to their ultra-small size, non-toxicity, biocompatibility, excellent photostability, tunable fluorescence, and water solubility. This review summarizes the recent research progress in the field of Fe-based nanostructures and places special emphases on their applications in chiral sensing and imaging. The synthetic strategies to prepare the targeted Fe-based structures were also introduced. The chiral sensing and imaging applications of the nanostructures are discussed in details.

Słowa kluczowe:

imaging, metasurfaces, quantum dots, sensing, terahertz

Afiliacje autorów:

Nwaji N.-IPPT PAN
Juyong G.-other affiliation
My‐Chi N.-other affiliation
Huu‐Quang N.-other affiliation
Hyojin K.-other affiliation
Youngeun C.-other affiliation
Youngmi K.-other affiliation
Hongxia C.-other affiliation
Jaebeom L.-Lexington High School (US)
140p.
3.Birhanu Bayissa G., Teshome Tufa L., Nwaji Njemuwa N., Xiaojun H., Lee J., Advances in All‑Solid‑State Lithium–Sulfur Batteries for Commercialization, Nano-Micro Letters, ISSN: 2150-5551, DOI: 10.1007/s40820-024-01385-6, Vol.16, pp.2-38, 2024

Streszczenie:

Solid-state batteries are commonly acknowledged as the forthcoming evolution
in energy storage technologies. Recent development progress for these rechargeable
batteries has notably accelerated their trajectory toward achieving commercial
feasibility. In particular, all-solid-state lithium–sulfur batteries (ASSLSBs) that rely
on lithium–sulfur reversible redox processes exhibit immense potential as an energy
storage system, surpassing conventional lithium-ion batteries. This can be attributed
predominantly to their exceptional energy density, extended operational lifespan, and
heightened safety attributes. Despite these advantages, the adoption of ASSLSBs in the
commercial sector has been sluggish. To expedite research and development in this particular
area, this article provides a thorough review of the current state of ASSLSBs. We
delve into an in-depth analysis of the rationale behind transitioning to ASSLSBs, explore
the fundamental scientific principles involved, and provide a comprehensive evaluation
of the main challenges faced by ASSLSBs. We suggest that future research in this field
should prioritize plummeting the presence of inactive substances, adopting electrodes with optimum performance, minimizing interfacial
resistance, and designing a scalable fabrication approach to facilitate the commercialization of ASSLSBs

Afiliacje autorów:

Birhanu Bayissa G.-other affiliation
Teshome Tufa L.-other affiliation
Nwaji Njemuwa N.-IPPT PAN
Xiaojun H.-other affiliation
Lee J.-Lexington High School (US)
140p.
4.Nwaji N., Fikadu B., Osial M., Moazzami Goudarzi Z., Asgaran S., Teshome Tufa L., Lee J., Giersig M., Disentangling the catalytic origin in defect engineered 2D NiCoMoS@Ni(CN)2 core-shell heterostructure for energy-saving hydrazine-assisted water oxidation, International Journal of Hydrogen Energy, ISSN: 0360-3199, DOI: 10.1016/j.ijhydene.2024.08.432, Vol.86, pp.554-563, 2024

Streszczenie:

The major hindrance to efficient electrocatalytic hydrogen generation from water electrolysis is the sluggish kinetics with corresponding large overvoltage of oxygen evolution reaction. Herein, we report a defective 2D NiCoMoS@Ni(CN)2 core-shell heterostructure derived from Hofmann-type MOF as an efficient and durable high-performance noble metal-free electrocatalyst for hydrazine oxidation reaction (HzOR) in alkaline media. The sluggish oxygen evolution reaction was replaced with a more thermodynamically favourable HzOR, enabling energy-saving electrochemical hydrogen production with 2D NiCoMoS@Ni(CN)2 acting as a bifunctional electrocatalyst for anodic HzOR and cathodic hydrogen generation. Operating at room temperature, the two-electrode electrolyzer delivers 100 mA cm−2 from a cell voltage of just 257 mV, with strong long-term electrochemical durability and nearly 100% Faradaic efficiency for hydrogen evolution in 1.0 M KOH aqueous solution with 0.5 M hydrazine. The density functional theory (DFT) was employed to investigate the origin of catalytic performance and showed that high vacancy creation within the heterointerface endowed NiCoMoS@Ni(CN)2 with favourable functionalities for excellent catalytic performance.

Słowa kluczowe:

Defect engineering, Core-shell, Electrocatalyst, Hydrazine oxidation, Heterostructure

Afiliacje autorów:

Nwaji N.-IPPT PAN
Fikadu B.-other affiliation
Osial M.-IPPT PAN
Moazzami Goudarzi Z.-IPPT PAN
Asgaran S.-other affiliation
Teshome Tufa L.-other affiliation
Lee J.-Lexington High School (US)
Giersig M.-IPPT PAN
140p.
5.Nwaji N., Fikadu B., Osial M., Gicha B.B., Warczak M., Fan H., Lee J., Giersig M., Atomically dispersed ruthenium in transition metal double layered hydroxide as a bifunctional catalyst for overall water splitting, RENEWABLE ENERGY, ISSN: 0960-1481, DOI: 10.1016/j.renene.2024.121307, Vol.235, pp.1-10, 2024

Streszczenie:

Efficient and sustainable energy conversion depends on the rational design of single-atom catalysts. The control of the active sites at the atomic level is vital for electrocatalytic materials in alkaline and acidic electrolytes. Moreover, fabrication of effective catalysts with a well-defined surface structure results in an in-depth understanding of the catalytic mechanism. Herein, a single atom ruthenium dispersed in nickel-cobalt layered hydroxide (Ru-NiCo LDH) is reported. Through the precise controlling of the atomic dispersion and local coordination environment, Ru-NiCo LDH//Ru-NiCo LDH provides an ultra-low overpotential of 1.45 mV at 10 mA cm−2 for the overall water splitting, which surpasses that of the state-of-the-art Pt/C/RuO2 redox couple. Density functional theory calculations show that Ru-NiCo LDH optimizes hydrogen evolution intermediate adsorption energies and promotes O-O coupling at a Ru-O active site for oxygen evolution, while Ni serves as the water dissociation site for effective water splitting. As a potential model, Ru-NiCo LDH shows enhanced water splitting performance with potential for the development of promising water-alkaline catalysts.

Afiliacje autorów:

Nwaji N.-IPPT PAN
Fikadu B.-other affiliation
Osial M.-IPPT PAN
Gicha B.B.-other affiliation
Warczak M.-Institute of Physical Chemistry, Polish Academy of Sciences (PL)
Fan H.-other affiliation
Lee J.-Lexington High School (US)
Giersig M.-IPPT PAN
140p.
6.Nwaji N., Getasew Mulualem Z., Juyong G., Hyojin K., Lemma Tushome T., Yujin C., Mahedra G., Hyeyoung S., Jaebeom L., Dimeric NiCo single-atom anchored on ultrathin N-doped 2D molybdenum carbide boosted performance in solid-state supercapacitor, Journal of Energy Storage, ISSN: 2352-152X, DOI: 10.1016/j.est.2024.110671, Vol.83, pp.1-10, 2024

Streszczenie:

Tuning the electronic structure of single-atom catalysts through dimeric single-atom formation could be an innovative approach to increasing their energy storage activity, but the process of achieving this is challenging. In this study, we designed a simple technique to obtain Nisingle bondCo single atom dimers (SADs) anchored on N-doped molybdenum carbide (N-Mo2C) through in-situ encapsulation of Nisingle bondCo into molybdenum polydopamine, followed by annealing with optimal tuning of nitrogen dopant. The Nisingle bondCo atomic level coordination was confirmed with X-ray absorption spectroscopy. When used as energy storage supercapacitor, The NiCo-SADs showed enhanced specific capacity (1004.8 F g−1 at 1 A g−1), enhanced rate capability (75 %), and exceptional cycling stability (93.6 % with 98.5 % coulombic efficiency) via a dominant capacitive charge storage. The augmented charge storage characteristics are attributed to the collaborative features of the active Nisingle bondCo constituents acting as electron reservoir for effective adsorption of HO− ion during the electrochemical process. The DFT study showed thermodynamically favorable OH− adsorption between the three metal bridges that promoted redox reaction kinetics and enhanced conductivity for the NiCo-SADs. When using N-Mo2C as the anode to fabricate hybrid supercapacitors, the device exhibits high energy density of 69.69 Wh kg−1 at power density of 8200 W kg−1, respectively and shows excellent long-term cycling stability (93.42 % after 3000 cycles), which affirms the potential of the assembled device for applications in solid state supercapacitors.

Afiliacje autorów:

Nwaji N.-IPPT PAN
Getasew Mulualem Z.-other affiliation
Juyong G.-other affiliation
Hyojin K.-other affiliation
Lemma Tushome T.-other affiliation
Yujin C.-other affiliation
Mahedra G.-other affiliation
Hyeyoung S.-other affiliation
Jaebeom L.-Lexington High School (US)
100p.
7.Zhang Y., Nwaji N., Wu L., Jin m., Zhou G., Giersig M., Wang X., Qiu T., Akinoglu E.M., MAPbBr3/Bi2WO6 Z-scheme-Heterojunction Photocatalysts for photocatalytic CO2 reduction, JOURNAL OF MATERIALS SCIENCE, ISSN: 0022-2461, DOI: 10.1007/s10853-023-09220-w, Vol.59, pp.1498-1512, 2024

Streszczenie:

Photocatalytic CO2 reduction has emerged as a promising strategy for converting solar energy into valuable chemicals, capturing the attention of scientists across various disciplines. Organic and inorganic perovskites, particularly methylammonium lead bromide (MAPbBr3), have demonstrated potential in this field due to their remarkable visible-light response and carrier transport properties. However, the catalytic performance of pristine MAPbBr3 has been limited by severe charge recombination, hindering its applicability in photocatalytic systems. Here, we show that a MAPbBr3/Bi2WO6 (MA/BWO) heterojunction significantly enhances photocatalytic CO2 reduction performance compared to individual pristine MA or BWO. This enhancement is evidenced by the superior performance of the 25% MA/BWO composite, which exhibits CO and CH4 release rates of 1.82 μmol/g/h and 0.08 μmol/g/h, respectively. This improvement is attributed to the direct Z-scheme heterojunction formed between MAPbBr3 and Bi2WO6, which facilitates efficient charge separation and suppresses charge recombination. The results challenge the previous understanding of MAPbBr3-based photocatalysts and demonstrate a novel approach for developing highly active organic and inorganic perovskite photocatalysts. The successful application of the MA/BWO heterojunction in photocatalytic CO2 reduction expands the scope of organic and inorganic perovskites in the field of renewable energy conversion. By providing a broader perspective, our findings contribute to the ongoing efforts towards sustainable energy solutions, appealing

Afiliacje autorów:

Zhang Y.-University of Notre Dame (US)
Nwaji N.-other affiliation
Wu L.-other affiliation
Jin m.-South China Normal University (CN)
Zhou G.-South China Normal University (CN)
Giersig M.-IPPT PAN
Wang X.-other affiliation
Qiu T.-other affiliation
Akinoglu E.M.-University of Melbourne (AU)
100p.
8.Yonas S., Gicha B.B., Adhikari S., Sabir F.K., Tran V.T., Nwaji N., Gonfa B.A., Teshome Tufa L., Electric-Field-Assisted Synthesis of Cu/MoS2 Nanostructures for Efficient Hydrogen Evolution Reaction, Micromachines, ISSN: 2072-666X, DOI: 10.3390/mi15040495, Vol.15, No.495, pp.1-13, 2024

Streszczenie:

Molybdenum sulfide–oxide (MoS2, MS) emerges as the prime electrocatalyst candidate demonstrating hydrogen evolution reaction (HER) activity comparable to platinum (Pt). This study presents a facile electrochemical approach for fabricating a hybrid copper (Cu)/MoS2 (CMS) nanos- tructure thin-film electrocatalyst directly onto nickel foam (NF) without a binder or template. The synthesized CMS nanostructures were characterized utilizing energy-ispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrochemical methods. The XRD result revealed that the Cu metal coating on MS results in the creation of an extremely crys-talline CMS nanostructure with a well-defined interface. The hybrid nanostructures demonstrated
higher hydrogen production, attributed to the synergistic interplay of morphology and electron dis-tribution at the interface. The nanostructures displayed a significantly low overpotential of −149 mV at 10 mA cm−2 and a Tafel slope of 117 mV dec−1, indicating enhanced catalytic activity compared to pristine MoS2.This research underscores the significant enhancement of the HER performance and
conductivity achieved by CMS, showcasing its potential applications in renewable energy.

Słowa kluczowe:

electrodeposition, hydrogen evolution reactions, catalytic activity, Cu/MoS2 nanostructures

Afiliacje autorów:

Yonas S.-other affiliation
Gicha B.B.-other affiliation
Adhikari S.-other affiliation
Sabir F.K.-other affiliation
Tran V.T.-other affiliation
Nwaji N.-IPPT PAN
Gonfa B.A.-other affiliation
Teshome Tufa L.-other affiliation
70p.
9.Birhanu Bayissa G., Teshome Tufa L., Mahendra G., Lee Y., Fikadu Banti B., Nwaji Njoku N., You S., Lee J., Oxygen Vacancy Generation and Stabilization in Layered NiFeCo Double Hydroxide Nanosheets for a Highly Efficient Oxygen Evolution Reaction, ACS Applied Nano Materials, ISSN: 2574-0970, DOI: 10.1021/acsanm.4c01840, Vol.8, pp.A-K, 2024

Streszczenie:

Oxygen vacancy (Vo) is ubiquitous, playing a critical role in tuning the electronic configuration and optimizing the adsorption of adsorbates in the oxygen evolution reaction (OER) process. However, fine control over the density and stabilization of Vo is a big challenge in the highly oxidizing environment of OER. Herein, we have fabricated bulk NiFeCo (layered double hydroxide) LDHs via the hydrothermal method and exfoliated them into thin sheets rich with Vo using high-energy Ar-plasma. We doped fluoride to simultaneously modulate the charge distribution of surrounding atoms and stabilize Vo by taking advantage of the extremely high electronegativity and similar ion diameter to oxygen of fluoride. The material exhibited OER activity with a low overpotential of 200 mV at 10 mA cm–2 and a Tafel slope of 34.6 mV dec–1. Density functional theory (DFT) calculations support the claim that Vo and fluoride substantially increase NiFeCo LDH OER activity by modifying the electronic structures of the catalytically active sites.

Słowa kluczowe:

Electrocatalyst, Double layered hydroxide, oxygen evolution reaction, oxygen vacancy, stabilization

Afiliacje autorów:

Birhanu Bayissa G.-other affiliation
Teshome Tufa L.-other affiliation
Mahendra G.-other affiliation
Lee Y.-other affiliation
Fikadu Banti B.-other affiliation
Nwaji Njoku N.-IPPT PAN
You S.-other affiliation
Lee J.-Lexington High School (US)
10.Nwaji Njemuwa N., Juyong G., Mahendra G., Hyojin K., Adewale Hammed P., Sharan A., Singh N., Lee J., Defect engineered Fe3C@NiCo2S4 trojan nanospike derived from Metal Organic framework as Advanced electrode material for Hybrid supercapacitor., ACS Applied Materials and Interfaces, ISSN: 1944-8244, DOI: 10.1021/acsami.3c04635, Vol.15, No.29, pp.34779-34788, 2023

Streszczenie:

The rational synthesis and tailoring of metal-organic frameworks (MOFs) with multifunctional micro/nanoarchitectures have emerged as a subject of significant academic interest owing to their promising potential for utilization in advanced energy storage devices. Herein, we explored a category of three-dimensional (3D) NiCo2S4 nanospikes that have been integrated into a 1D Fe3C microarchitecture using a chemical surface transformation process. The resulting electrode materials, i.e., Fe3C@NiCo2S4 nanospikes, exhibit immense potential for utilization in high-performance hybrid supercapacitors. The nanospikes exhibit an elevated specific capacity (1894.2 F g-1 at 1 A g-1), enhanced rate capability (59%), and exceptional cycling stability (92.5% with 98.7% Coulombic efficiency) via a charge storage mechanism reminiscent of a battery. The augmented charge storage characteristics are attributed to the collaborative features of the active constituents, amplified availability of active sites inherent in the nanospikes, and the proficient redox chemical reactions of multi-metallic guest species. When using nitrogen-doped carbon nanofibers as the anode to fabricate hybrid supercapacitors, the device exhibits high energy and power densities of 62.98 Wh kg-1 and 6834 W kg-1, respectively, and shows excellent long-term cycling stability (95.4% after 5000 cycles), which affirms the significant potential of the proposed design for applications in hybrid supercapacitors. The DFT study showed the strong coupling of the oxygen from the electrolyte OH- with the metal atom of the nanostructures, resulting in high adsorption properties that facilitate the redox reaction kinetics.

Słowa kluczowe:

defect engineering,Nanospike,advanced electrode,hybrid,MOF,Supercapacitor

Afiliacje autorów:

Nwaji Njemuwa N.-other affiliation
Juyong G.-other affiliation
Mahendra G.-other affiliation
Hyojin K.-IPPT PAN
Adewale Hammed P.-other affiliation
Sharan A.-other affiliation
Singh N.-other affiliation
Lee J.-Lexington High School (US)
200p.
11.Mahendra G., Huu-Quang N., Sohyun K., Birhanu Bayissa G., Teshome Tufa L., Nwaji Njemuwa N., My-Chi Thi N., Juyong G., Lee J., Rugged forest morphology of magnetoplasmonic nanorods that collect maximum light for photoelectrochemical water splitting, Nano Micro Small Journal, ISSN: 1613-6829, DOI: 10.1002/smll.202302980, Vol.19, pp.1-14, 2023

Streszczenie:

A feasible nanoscale framework of heterogeneous plasmonic materials and
proper surface engineering can enhance photoelectrochemical (PEC)
water-splitting performance owing to increased light absorbance, efficient
bulk carrier transport, and interfacial charge transfer. This article introduces a
new magnetoplasmonic (MagPlas) Ni-doped Au@FexOy nanorods (NRs)
based material as a novel photoanode for PEC water-splitting. A two stage
procedure produces core–shell Ni/Au@FexOy MagPlas NRs. The first-step is
a one-pot solvothermal synthesis of Au@FexOy. The hollow FexOy nanotubes
(NTs) are a hybrid of Fe2O3 and Fe3O4, and the second-step is a sequential
hydrothermal treatment for Ni doping. Then, a transverse magnetic
field-induced assembly is adopted to decorate Ni/Au@FexOy on FTO glass to
be an artificially roughened morphologic surface called a rugged forest,
allowing more light absorption and active electrochemical sites. Then, to
characterize its optical and surface properties, COMSOL Multiphysics
simulations are carried out. The core–shell Ni/Au@FexOy MagPlas NRs
increase photoanode interface charge transfer to 2.73 mAcm−2 at 1.23 V RHE.
This improvement is made possible by the rugged morphology of the NRs,
which provide more active sites and oxygen vacancies as the hole transfer
medium. The recent finding may provide light on plasmonic photocatalytic
hybrids and surface morphology for effective PEC photoanodes.

Afiliacje autorów:

Mahendra G.-other affiliation
Huu-Quang N.-other affiliation
Sohyun K.-other affiliation
Birhanu Bayissa G.-other affiliation
Teshome Tufa L.-other affiliation
Nwaji Njemuwa N.-IPPT PAN
My-Chi Thi N.-other affiliation
Juyong G.-other affiliation
Lee J.-Lexington High School (US)
200p.
12.Nwaji N., Akinoglu E.M., Lin Q., Teshome Tufa L., Sharan A., Singh N., Wang X., Giersig M., Lee J., Surface Modulation of Fe3O4 Confined in Porous Molybdenum-Based Nanoplatform for Enhanced Hydrogen Production, Energy Technology, ISSN: 2194-4296, DOI: 10.1002/ente.202201061, Vol.11, No.2, pp.2201061-1-9, 2023

Streszczenie:

The integration of different precursor components to form single nanostructures via one-step synthesis process is mostly restricted by the compatibility and complexity of components. Herein, a highly uniform, spherical, hollowed, and hierarchical iron oxide-wrapped Mo–polydopamine is synthesized using a one-pot liquid-phase reaction at room temperature. Mo2C is doped with Fe3O4 to harness the rich electrons in Fe dopants for effective lowering of the unoccupied d-orbitals in Mo. The surface conductivity of the as-prepared nanostructures is enhanced by decorating them with gold nanoparticles utilizing strong interaction of Au and amine. The nanocomposites are converted into carbidic hollowed structures via an annealing process without any distortion in morphology. The well-organized structure and nanosize of the particles provide efficient catalytic performance for hydrogen evolution reaction in acidic media. MoFe–C@Au exhibits a very positive onset potential of 2 mV, low Tafel slope of 50.1 mV dec^-1, and remarkable long- term stability.

Słowa kluczowe:

electrocatalysts,hierarchical syntheses,hydrogen evolution,molybdenum,polydopamine

Afiliacje autorów:

Nwaji N.-other affiliation
Akinoglu E.M.-University of Melbourne (AU)
Lin Q.-other affiliation
Teshome Tufa L.-other affiliation
Sharan A.-other affiliation
Singh N.-other affiliation
Wang X.-other affiliation
Giersig M.-IPPT PAN
Lee J.-Lexington High School (US)
100p.
13.Cheru Fekadu M., Bedasa Abdisa G., Fedlu Kedir S., Birhanu Bayissa G., Nwaji N., Lemma Teshome T., Jaebeom L., Ni-Based Ultrathin Nanostructures for Overall Electrochemical Water Splitting, Material Chemistry Frontiers, ISSN: 2052-1537, DOI: 10.1039/D2QM00964A, Vol.7, pp.194-215, 2023

Streszczenie:

Hydrogen produced by electrochemical water splitting is considered to be a sustainable fuel source, an
ideal way to solve the energy problem and its environmental challenges. However, industrial production
of hydrogen from water splitting is mainly hindered by sluggish kinetics of the oxygen evolution reaction
(OER) at the anode and the hydrogen evolution reaction (HER) at the cathode in an alkaline solution due
to the difficulty in forming binding protons. Thus, the construction of a highly active and cost-effective
catalyst with abundant oxygen vacancies is critical for enhancing the reaction efficiency and decreasing
the required overpotential. Due to earth-abundance and electrocatalytic activities, Ni-based ultrathin
nanostructures (Ni-utNSs) have attracted immense attention for overall water splitting. Herein, we have
presented a complete summary of recent advancements in Ni-utNSs for overall electrochemical water
splitting. After discussing unique advances in Ni-utNSs, we discussed their properties and crystal
structures. The HER, OER, and oxygen reduction reaction (ORR) mechanisms were briefly discussed. We
also discussed several Ni-utNS manufacturing techniques, as well as in situ and ex situ characterization
and computer modeling. Furthermore, the electrochemical water splitting of Ni-utNSs is addressed. This
review can help readers understand the recent progress of Ni-utNS catalysts and gain insight into the
rational design of Ni-utNS catalysts with high electrocatalytic activity.

Afiliacje autorów:

Cheru Fekadu M.-other affiliation
Bedasa Abdisa G.-other affiliation
Fedlu Kedir S.-other affiliation
Birhanu Bayissa G.-other affiliation
Nwaji N.-IPPT PAN
Lemma Teshome T.-other affiliation
Jaebeom L.-Lexington High School (US)
14.Nwaji Njemuwa N., Hyojin K., Mahendra G., Teshome Tufa L., Juyong G., Sharan A., Singh N., Lee J., Sulfur vacancy induced Co3S4@CoMo2S4 nanocomposite as functional electrode for high performance supercapacitor, Journal of Materials Chemistry A, ISSN: 2050-7488, DOI: 10.1039/d2ta08820g, Vol.11, pp.3640-3652, 2023

Streszczenie:

Vacancy engineering offers an attractive approach to improving the surface properties and electronic
structure of transition metal nanomaterials. However, simple and cost-effective methods for introducing
defects into nanomaterials still face great challenges. Herein, we propose a facile room temperature
two-step technique that utilizes Fe as the dopant to enhance S vacancies in cobalt-based metal–organic
frameworks (MOFs). The Fe–Co-MOF was converted into a hollow Fe–Co3S4 confined in CoMo2S4 to
form Fe–Co3S4@CoMo2S4 nanosheets. The as-prepared material showed enhanced charge storage
kinetics and excellent properties as an electrode material for supercapacitors. The obtained
nanostructure displayed a high specific capacitance (980.3 F g−1 at 1 A g−1) and excellent cycling stability
(capacity retention of 96.5% after 6000 cycles at 10 A g−1). Density functional theory (DFT) calculations
show that introducing defects into the nanostructures leads to more electrons appearing near the Fermi
level, which is beneficial for electron transfer during electrochemical processes. Thus, this work provides
a rational cost-effective strategy for introducing defects into transition metal sulfides and may serve as
a potential means to prepare electrode materials for energy storage.

Afiliacje autorów:

Nwaji Njemuwa N.-other affiliation
Hyojin K.-other affiliation
Mahendra G.-other affiliation
Teshome Tufa L.-other affiliation
Juyong G.-other affiliation
Sharan A.-other affiliation
Singh N.-other affiliation
Lee J.-Lexington High School (US)
15.Achadu Ojodomo J., Nwaji N., Lee D., Lee J., Akinoglu E.M., Giersig M., Park Enoch Y., 3D hierarchically porous magnetic molybdenum trioxide@gold nanospheres as a nanogap-enhanced Raman scattering biosensor for SARS-CoV-2, Nanoscale Advances, ISSN: 2516-0230, DOI: 10.1039/d1na00746g, Vol.4, pp.871-883, 2022

Streszczenie:

The global pandemic of COVID-19 is an example of how quickly a disease-causing virus can take root and threaten our civilization. Nowadays, ultrasensitive and rapid detection of contagious pathogens is in high demand. Here, we present a novel hierarchically porous 3-dimensional magnetic molybdenum trioxide–polydopamine-gold functionalized nanosphere (3D mag-MoO3–PDA@Au NS) composed of plasmonic, semiconductor, and magnetic nanoparticles as a multifunctional nanosculptured hybrid. Based on the synthesized 3D mag-MoO3–PDA@Au NS, a universal “plug and play” biosensor for pathogens is proposed. Specifically, a magnetically-induced nanogap-enhanced Raman scattering (MINERS) detection platform was developed using the 3D nanostructure. Through a magnetic actuation process, the MINERS system overcomes Raman signal stability and reproducibility challenges for the ultrasensitive detection of SARS-CoV-2 spike protein over a wide dynamic range up to a detection limit of 10−15 g mL−1. The proposed MINERS platform will facilitate the broader use of Raman spectroscopy as a powerful analytical detection tool in diverse fields.

Afiliacje autorów:

Achadu Ojodomo J.-other affiliation
Nwaji N.-other affiliation
Lee D.-other affiliation
Lee J.-Lexington High School (US)
Akinoglu E.M.-University of Melbourne (AU)
Giersig M.-IPPT PAN
Park Enoch Y.-other affiliation
20p.
16.Refilwe M., Nwaji Njemuwa N., Muthumuni M., Zhi-Long C., Tebello N., Photodynamic therapy characteristics of phthalocyanines in the presence of boron doped detonation nanodiamonds: Effect of symmetry and charge, Phothodygnosis, ISSN: 1873-1597, DOI: 10.1016/j.pdpdt.2021.102705, Vol.37, pp.1-9, 2022

Streszczenie:

The synthesis, photophysicochemical and photodynamic therapy (PDT) activities of benzothiazole substituted zinc phthalocyanine (Pc): 1 (asymmetrically substituted and composed of no charges), 2 (asymmetrically substituted and composed of three positive charges), and 3 (symmetrically substituted and composed of four positive charges), are presented. The triplet and singlet oxygen quantum yields were highest for complex 2 showing the importance of asymmetry and charge. The complexes are covalently and non-covalently linked to B doped detonation nanodiamonds (B@DNDs) to yield nanohybrids (B@DNDs-1, B@DNDs-2, B@DNDs-3). The presence of B@DNDs, asymmetry and positive charge resulted in improved PDT with the lowest cell viability being observed for B@DNDs-2 at 5%. The cell viability ranged from 5% to 7% for the nanohybrids compared to 19–26% for Pcs alone.

Afiliacje autorów:

Refilwe M.-other affiliation
Nwaji Njemuwa N.-IPPT PAN
Muthumuni M.-other affiliation
Zhi-Long C.-other affiliation
Tebello N.-other affiliation
17.Nwaji N., Akinoglu E.M., Biyun L., Xin W., Michael G., One-Pot Synthesis of One-Dimensional Multijunction Semiconductor Nanochains from Cu1.94S, CdS, and ZnS for Photocatalytic Hydrogen Generation., ACS Applied Materials and Interfaces, ISSN: 1944-8244, DOI: 10.1021/acsami.1c18020, Vol.49, pp.58630-58639, 2021

Streszczenie:

Chains of alternating semiconductor nanocrystals are complex nanostructures that can offer control over photogenerated charge carriers dynamics and quantized electronic states. We develop a simple one-pot colloidal synthesis of complex Cu1.94S-CdS and Cu1.94S-ZnS nanochains exploiting an equilibrium driving ion exchange mechanism. The chain length of the heterostructures can be tuned using a concentration dependent cation exchange mechanism controlled by the precursor concentrations, which enables the synthesis of monodisperse and uniform Cu1.94S-CdS-Cu1.94S nanochains featuring three epitaxial junctions. These seamless junctions enable efficient separation of photogenerated charge carriers, which can be harvested for photocatalytic applications. We demonstrate the superior photocatalytic activity of these noble metal free materials through solar hydrogen generation at a hydrogen evolution rate of 22.01 mmol g–1 h–1, which is 1.5-fold that of Pt/CdS heterostructure photocatalyst particles.

Afiliacje autorów:

Nwaji N.-IPPT PAN
Akinoglu E.M.-University of Melbourne (AU)
Biyun L.-other affiliation
Xin W.-other affiliation
Michael G.-IPPT PAN
200p.
18.Nwaji N., Akinoglu E.M., Giersig M., Gold nanoparticle-decorated Bi2S3 nanorods and nanoflowers for photocatalytic wastewater treatment, Catalysts, ISSN: 2073-4344, DOI: 10.3390/catal11030355, Vol.11, No.3, pp.355-1-12, 2021

Streszczenie:

Colloidal synthesis of photocatalysts with potential to overcome the drawback of low photocatalytic efficiency brought by charge recombination and narrow photo-response has been a challenge. Herein, a general and facile colloidal approach to synthesize orthorhombic phase Bi2S3 particles with rod and flower-like morphology is reported. We elucidate the formation and growth process mechanisms of these synthesized nanocrystals in detail and cooperate these Bi2S3 particles with metallic gold nanoparticles (AuNPs) to construct heterostructured photocatalysts. The unique properties of AuNPs featuring tunable surface plasmon resonance and large field enhancement are used to sensitize the photocatalytic activity of the Bi2S3 semiconductor particles. The morphology, structure, elemental composition, and light absorption ability of the prepared catalysts are characterized by (high-resolution) transmission electron microscopy, scanning electron microscopy, X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, and UV–vis absorption spectroscopy. The catalysts exhibit high and stable photocatalytic activity for the degradation of organic pollutants demonstrated using rhodamine B and methyl orange dyes under solar light irradiation. We show that the incorporation of the AuNPs with the Bi2S3 particles increases the photocatalytic activity 1.2 to 3-fold. Radical trapping analysis indicates that the production of hydroxyl and superoxide radicals are the dominant active species responsible for the photodegradation activity. The photocatalysts exhibit good stability and recyclability.

Słowa kluczowe:

Bi2S3, nanoflower, nanorod, photocatalysis, heterostructures, AuNPs

Afiliacje autorów:

Nwaji N.-other affiliation
Akinoglu E.M.-University of Melbourne (AU)
Giersig M.-IPPT PAN
100p.
19.Gabriele V.R., Mazhabi R.M., Alexander N., Mukherjee P., Seyfried T.N., Nwaji N., Akinoglu E.M., Mackiewicz A., Zhou G., Giersig M., Naughton M.J., Kempa K., Light- and melanin nanoparticle-induced cytotoxicity in metastatic cancer cells, Pharmaceutics, ISSN: 1999-4923, DOI: 10.3390/pharmaceutics13070965, Vol.13, No.7, pp.965-1-14, 2021

Streszczenie:

Melanin nanoparticles are known to be biologically benign to human cells for a wide range of concentrations in a high glucose culture nutrition. Here, we show cytotoxic behavior at high nanoparticle and low glucose concentrations, as well as at low nanoparticle concentration under exposure to (nonionizing) visible radiation. To study these effects in detail, we developed highly monodispersed melanin nanoparticles (both uncoated and glucose-coated). In order to study the effect of significant cellular uptake of these nanoparticles, we employed three cancer cell lines: VM-M3, A375 (derived from melanoma), and HeLa, all known to exhibit strong macrophagic character, i.e., strong nanoparticle uptake through phagocytic ingestion. Our main observations are: (i) metastatic VM-M3 cancer cells massively ingest melanin nanoparticles (mNPs); (ii) the observed ingestion is enhanced by coating mNPs with glucose; (iii) after a certain level of mNP ingestion, the metastatic cancer cells studied here are observed to die—glucose coating appears to slow that process; (iv) cells that accumulate mNPs are much more susceptible to killing by laser illumination than cells that do not accumulate mNPs; and (v) non-metastatic VM-NM1 cancer cells also studied in this work do not ingest the mNPs, and remain unaffected after receiving identical optical energy levels and doses. Results of this study could lead to the development of a therapy for control of metastatic stages of cancer.

Słowa kluczowe:

melanoma, melanin nanoparticles, cytotoxicity, laser medical applications, hyperthermia

Afiliacje autorów:

Gabriele V.R.-other affiliation
Mazhabi R.M.-South China Normal University (CN)
Alexander N.-other affiliation
Mukherjee P.-other affiliation
Seyfried T.N.-other affiliation
Nwaji N.-other affiliation
Akinoglu E.M.-University of Melbourne (AU)
Mackiewicz A.-other affiliation
Zhou G.-South China Normal University (CN)
Giersig M.-IPPT PAN
Naughton M.J.-other affiliation
Kempa K.-other affiliation
100p.
20.Nwaji N., Akinoglu E.M., Synthesis of ZnS-CuS-Bi nanonail heterostructures and funnel mechanism of their photocatalytic activity, Journal of Environmental Chemical Engineering, ISSN: 2213-2929, DOI: 10.1016/j.jece.2021.106066, Vol.9, pp.1-7, 2021

Streszczenie:

Nanonail shaped ZnS-CuS-Bi three component nanoparticles are synthesized via a simple one-pot colloidal
synthesis route by thermal decomposition of metal-thiolate precursors. A thiol serves as the sulfur source and a
phase directing capping agent promotes selective anisotropic growth of the nanocrystals in a noncoordinating
solvent. After the nucleation and growth of a CuS rod, reactive Cu ions serve as catalytic seeds for the nucleation
and growth of ZnS and Bi at the CuS nanorod tips. Thereby the obtained ZnS-CuS-Bi nanocrystals form a chain of
two semiconductors of decreasing band gap and a metallic Bi nanoparticle. The three components absorb light in
different spectral regions enabling efficient light harvesting. Furthermore, the band edge alignment of ZnS and
CuS promote photogenerated electron funneling towards the Bi catalyst particle, which promotes charge carrier
separation, effectively channeling the catalytic activity. The photocatalytic performance is assessed at the
example of the photodegradation of the organic dye Rhodamine B, and shows excellent performance rendering
these nanonails as inexpensive, non-toxic and efficient photocatalyst to remedy environmental pollution

Afiliacje autorów:

Nwaji N.-IPPT PAN
Akinoglu E.M.-University of Melbourne (AU)
21.Nnaemeka N., Nwaji N., John M., Tebello N., Ball-type phthalocyanines and reduced graphene oxide nanoparticles as separate and combined corrosion inhibitors of aluminium in HCl, Journal of molecular structure, ISSN: 0022-2860, DOI: 10.1016/j.molstruc.2021.130279, Vol.1236, pp.1-12, 2021

Streszczenie:

Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were
investigated for reduced graphene oxide nanosheets (rGONS), tetrakis-[4,4
-((4-(benzo[d]thiazol-2-yl)-
1,2-bis(phenoxy)] (diphthalocyaninato gallium (III) chloride) (2) and tetrakis-4-(hexadecane-1,2-dioxyl)-
bis(phthalocyaninato gallium(III) chloride) (1). Corrosion inhibition effects of rGONS, 1 and 2 were evaluated alone and in combination in 1.0 M hydrochloric acid solution using electrochemical techniques. The
mechanism of aluminum corrosion inhibition revealed predominantly anodic character for rGONS and
predominantly cathodic character for 1, 2, and conjugates with rGONS . The polarization technique gave
inhibition efficiency values of 96.5% and 96.9% respectively for 1 and 2, which increased in the presence
of rGONS to 97.4% and 98.1%, respectively, for the highest concentrations of 1 and 2. Scanning electron
microscopy revealed effective metal surface protection by the inhibitors by formation of protective films

Afiliacje autorów:

Nnaemeka N.-other affiliation
Nwaji N.-IPPT PAN
John M.-other affiliation
Tebello N.-other affiliation
22.Anthony C. E., Dickson N. U., Nwaji Njemuwa N., Olawale J. O., Obianuju L. N., Miracle E., Christopher U. S., Obinna O. O., David O. I., Green synthesis of silver nanoparticles using leaf extract of Euphorbia sanguine: an in vitro study of its photocatalytic and melanogenesis inhibition activity, Inorganic nano-metal chemistry, ISSN: 2470-1564, DOI: 10.1080/24701556.2021.1891100, Vol.49, pp.1-8, 2020

Streszczenie:

We report on biosynthesis of silver nanoparticles using aqueous leaf extract of Euphorbia sanguinea and its photocatalytic degradation of Congo red dye and melanogenesis inhibition activity of mushroom tyrosine enzyme. Surface Plasmon resonance bands obtained from UV-Vis spectra were within the range 430–436 nm. FT-IR studies reveal the presence of functional groups of the plant metabolites used as stabilizing agents of nanoparticles. The shape of silver nanoparticles is spherical with size ranges about 20–28.8 nm as confirmed by SEM. XRD patterns displayed well-defined crystalline peaks corresponding to the face-centred cubic structures of metallic silver nanoparticles. The results of photocatalysis showed high photocatalytic efficiency of 86% and 90% within 5 min and 60 min, respectively at a rate of solar radiation of in the degradation of Congo red dye. The AgNPs gave dose dependent melanogenesis inhibition activity with IC50 of 71.96 µg/ml, showing non competitive mode of inhibition

Afiliacje autorów:

Anthony C. E.-other affiliation
Dickson N. U.-other affiliation
Nwaji Njemuwa N.-IPPT PAN
Olawale J. O.-other affiliation
Obianuju L. N.-other affiliation
Miracle E.-other affiliation
Christopher U. S.-other affiliation
Obinna O. O.-other affiliation
David O. I.-other affiliation
23.Anthony C. E., Dickson N. U., Nwaji N., Obinna O. O., Chimerem O. E., Sandra I. M., Olawale J. O., Obianuju L. N., Green Synthesis of Biogenic Zinc Oxide Nanoflower as Dual Agent for Photodegradation of an Organic Dye and Tyrosinase Inhibitor, Journal of Inorganic and Organometallic Polymers and Materials, ISSN: 1574-1451, DOI: 10.1007/s10904-020-01729-w, Vol.31, pp.886-896, 2020

Streszczenie:

In the study, metabolites of Euphorbia sanguinea were used as benign reducing and stabilizing agents to obtain zinc oxide
nanoparticles (ZnO-NPs). The nanoparticles were evaluated as dual agent for photodegradation of Malachite green dye and
tyrosinase inhibitior of mushroom tyrosine enzyme. Surface plasmon bands and energy band gaps of the ZnO-NPs were
within the range 356–378 nm and 2.72–4.37 eV respectively as obtained from the UV–Vis spectra. SEM/EDS elemental
mapping of the nanoparticles gave flower-like shape and even distribution of zinc and oxygen. XRD result revealed crystallographic
peaks assigned to hexagonal phase of zinc oxide. The metal oxide nanoparticles were used to achieve 53% percentage
degradation of Malachite green dye solution in less than a minute of solar radiation, which increased to 92% in 60 min.
A first order kinetics with correlation coefficient R2
of 0.937, rate constant of 0.0084 min−1 and half-life of 82.52 min was
established for the photodegradation process. The ZnONPs exhibited good tyrosinase inhibition with IC50 of 49.016 μg/ml.
The mode of enzymatic inhibition was competitive with an inhibition constant (Ki) of 0.525 mM using Lineweaver–Burk
kinetic model.

Afiliacje autorów:

Anthony C. E.-other affiliation
Dickson N. U.-other affiliation
Nwaji N.-IPPT PAN
Obinna O. O.-other affiliation
Chimerem O. E.-other affiliation
Sandra I. M.-other affiliation
Olawale J. O.-other affiliation
Obianuju L. N.-other affiliation
24.Refilwe M., Tendamudzimu T., Muthumuni M., Nwaji N., Kevin L., Tebello N., Theoretical and photodynamic therapy characteristics of heteroatom doped detonation nanodiamonds linked to asymmetrical phthalocyanine for eradication of breast cancer cells, Journal of Luminescence, ISSN: 0022-2313, DOI: 10.1016/j.jlumin.2020.117465, Vol.227, pp.1-13, 2020

Streszczenie:

An amide mono substituted benzothiozole phthalocyanine: zinc(II) 3-(4-((3,17,23-tris(4-(benzo [d]thiazol-2-yl)
phenoxy)-9-yl)oxy) phenyl)amide phthalocyanine (NH2BzPc) was covalently linked to undoped and heteroatom
doped detonation nanodiamonds (DNDs): B@DNDs, P@DNDs, S@DNDs, N@DNDs, and S&N@DNDs There is a
drastic decrease in highest occupied molecular orbital (HOMO) – lowest unoccupied molecular orbital (LUMO)
energy gaps for nanoconjugates compared to DNDs alone. B@DNDs-NH2BzPc, S&N@DNDs-NH2BzPc, and
P@DNDs-NH2BzPc showed superior photodynamic therapy (PDT) effects. DNDs-NH2BzPc also had a small
HOMO-LUMO gap, but did not show improved PDT activity compared to the Pc alone, suggesting doping of
DNDs is important. This study shows improved PDT effect on Michigan Cancer Foundation-7 breast cancer lines
at 7.63%, 7.62% and 6.5% cell viability for P@DNDs-NH2BzPc, S&N@DNDs-NH2BzPc and B@DNDs-NH2BzPc,
respectively

Afiliacje autorów:

Refilwe M.-other affiliation
Tendamudzimu T.-other affiliation
Muthumuni M.-other affiliation
Nwaji N.-other affiliation
Kevin L.-other affiliation
Tebello N.-other affiliation
25.Shereen A. M., Nwaji N., John M., Tebello N., Saad M., Nonlinear optical responses of carbazole-substituted phthalocyanines conjugated to graphene quantum dots and in thin films , Journal of Luminescence, ISSN: 0022-2313, DOI: 10.1016/j.jlumin.2019.04.034, Vol.213, pp.88-97, 2019

Streszczenie:

hree different phthalocyanine complexes substituted with carbazoles were conjugated to graphene quantum dots (GQDs) through π–π stacking. The morphologies, sizes, and crystallinities of the nanoconjugates were determined using Raman spectroscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray diffraction. The nonlinear optical (NLO) properties of the metallophthalocyanines alone and when conjugated to the GQD nanomaterial in different solvents, as well as after having been embedded in thin films, were studied. The effects of the different substituents and solvents on the NLO properties of the metallophthalocyanines were evaluated. Enhancements in the photophysical properties of the complexes upon conjugation with the nanomaterial were observed. Fluorescence quantum yields, fluorescence lifetimes, triplet quantum yields, and triplet lifetimes were measured for the complexes, and for their conjugates in DMSO.

Afiliacje autorów:

Shereen A. M.-other affiliation
Nwaji N.-IPPT PAN
John M.-other affiliation
Tebello N.-other affiliation
Saad M.-other affiliation
26.Edith D., David O. O., Nwaji N., Earl P., Tebello N., Photophysicochemical and photodynamic therapy properties of metallophthalocyanines linked to gold speckled silica nanoparticles., Photodiagnosis and Photodynamic Therapy, ISSN: 1572-1000, DOI: 10.1016/j.pdpdt.2019.01.019, Vol.25, pp.325-333, 2019

Streszczenie:

This work reports on the linkage of 2(3),9(10),16(17),23(24) tetrakis [(benzo[d]thiazol-2-yl phenoxy) phthalocyaninato] zinc(II) (1) and indium(III) chloride (2) to gold speckled silica (GSS) nanoparticles via gold to
sulphur (Au-S) and gold to nitrogen (Au-N) self-assembly to form the conjugates: 1-GSS and 2-GSS. The formed
conjugates were characterized using microscopic and spectroscopic techniques, and the photophysicochemical
properties and photodynamic therapy (PDT) activity against human breast adenocarcinoma cell line (MCF-7
cells) were studied. The conjugates afforded decrease in fluorescence quantum yields with corresponding increase in triplet and singlet oxygen quantum yields when compared to phthalocyanines alone. Singlet oxygen is
cytotoxic to cancer cells hence it is important for PDT. The in vitro dark toxicity of complex 2 and 2-GSS against
MCF–7 cells showed ≥93% viable cells within concentration ranges of 10–160 μg/mL. 2–GSS showed enhanced
PDT activity with less than 50% viable cells at 80 μg/mL as compared to 2 and GSS alone which showed > 60%
viable cells within 10–160 μg/mL. The observed improvements in the PDT activity of 2-GSS could be attributed
to the high singlet oxygen generation of 2-GSS compared to 2 alone in addition to the phototoxicity of GSS.

Afiliacje autorów:

Edith D.-other affiliation
David O. O.-other affiliation
Nwaji N.-other affiliation
Earl P.-other affiliation
Tebello N.-other affiliation
27.Nnaemeka N., Nwaji N., Gertrude F., John M., Tebello N., Inhibition of Aluminium Corrosion Using Benzothiazole and Its Phthalocyanine Derivative, Electrocatlysis, ISSN: 1868-5994, DOI: 10.1007/s12678-019-00538-1, Vol.10, pp.445-458, 2019

Streszczenie:

Cyclic voltammetry and potentiodynamic polarization techniques were used to study the effects of 4-[4-(1,3-benzothiazol-
2yl)phenoxy] phthalonitrile (BT) and tetrakis[(benzo[d]thiazol-2ylphenoxy) phthalocyaninato] gallium(III)chloride
(ClGaBTPc) as aluminium corrosion inhibitors in 1.0 M hydrochloric acid. The presence of the inhibitors in the concentration
range of 2 to 10 μM was found to retard the aluminium corrosion process such that the inhibition efficiency was found to range
from 28.2 to 76.1%for BTand from 71.5 to 82.7%for ClGaBTPc. The latter was a better inhibitor. Scanning electronmicroscopy
and energy-dispersive X-ray measurements reveal effective metal surface protection by the inhibitors, most probably by shielding
it from the corrosion attacks of Cl− from the acid. The calculated quantum chemical parameters agreed with experimental results

Afiliacje autorów:

Nnaemeka N.-other affiliation
Nwaji N.-IPPT PAN
Gertrude F.-other affiliation
John M.-other affiliation
Tebello N.-other affiliation
28.Adachukwu Nwaka N., Pius Oziri U., William Robert W., Nwaji N., Karl F., Fatty acid profile and production of fatliquor from Canarium schweinfurthii mesocarp oil. Pertanika , Pertanika Journal of Science and Technology, ISSN: 0128-7680, Vol.27, pp.2221-2243, 2019

Streszczenie:

Fatty acid profile of Canarium schweinfurthii mesocarp oil was determined by GC-MS.
Sulphonated fatliquor was synthesized from the oil and characterized by FT-IR, 1
H NMR,
13C NMR, and DSC. The fatliquor was applied onto light leather in the processing of
leather shoe upper and physical tests carried out on the fixed leather. The sulphonated C.
schweinfurthii mesocarp oil had good characteristics as a leather fatliquor as shown by
the physical and strength properties of the fatliquored leather. In addition, a significantly
opened up structure of the leather treated with the prepared sulphonated oil was observed
as indicated from the Scanning Electron Microscopy (SEM) images. The features of the
processed trial leathers were comparable with similar leather made with commercially
available fatliquor

Afiliacje autorów:

Adachukwu Nwaka N.-other affiliation
Pius Oziri U.-other affiliation
William Robert W.-other affiliation
Nwaji N.-IPPT PAN
Karl F.-other affiliation
29.Nnaemeka N., Nwaji N., John M., Tebello N., Corrosion Resistance of Aluminum against Acid Activation: Impact of Benzothiazole-Substituted Gallium Phthalocyanine, Molecules, ISSN: 1420-3049, DOI: 10.3390/molecules24010207, Vol.24, pp.4-22, 2019

Streszczenie:

This study describes the adsorption behavior of organic inhibitors at the aluminum-HCl
solution interface and their corrosion inhibition performance. The organic inhibitors employed are:
4-(benzo [d]thiazol-2ylthio)phthalonitrile (BTThio) and tetrakis[(benzo[d]thiazol-2-yl-thio)phthalocyaninato]
gallium(III) chloride (ClGaBTThioPc). The corrosion behavior of these inhibitors is
investigated using electrochemical and computational techniques. Open circuit potential results
reveal predominant cathodic character for the mechanism of aluminum corrosion inhibition by the
inhibitors. Inhibition efficiency values from potentiodynamic polarization measurements increase
from 46.9 to 70.8% for BTThio and 59.7 to 81.0% for ClGaBTThioPc within the concentration range of
2 to 10 M. Scanning electron microscopy (SEM) measurements reveal protection of the metal surface
from acid attack, in the presence of the inhibitors and energy dispersive X-ray (EDX) measurements
show that the most probable way by which the inhibitors protect the metal surface would be
by shielding it from the corrosion attacks of Cl

Afiliacje autorów:

Nnaemeka N.-other affiliation
Nwaji N.-IPPT PAN
John M.-other affiliation
Tebello N.-other affiliation
30.Gertrude F., Nwaji N., Tebello N., Low symmetric metallophthalocyanine modified electrode via click chemistry for simultaneous detection of heavy metals, Journal of Electroanalytical Chemistry, ISSN: 1572-6657, DOI: 10.1016/j.jelechem.2018.02.016, Vol.813, pp.58-66, 2018

Streszczenie:

Beside different methods and materials used to develop electrochemical sensors, the modification of the electrode using click reaction based on metallophthalocyanine (MPc) compounds are shown to improve the stability and sensitivity of the sensor. This work reported the development of electrochemical sensor for mercury (II), Lead (II), copper (II) and cadmium (II) ions detection based on the synthesized novel low symmetry alkyne terminated cobalt Phthalocyanine (CoPc) derivative. Differential pulse stripping voltammetry (DPSV) technique was employed for the first time in simultaneous determination of trace levels of the above metal ions using modified glassy carbon electrode (GCE) via click chemistry. Under the optimum experimental conditions, the anodic peak current is proportional to the concentrations of metal ions over a wide range of 0 to 0.1 mM with nanolevel detection limit of 81.94, 327.71, 55.87 and 347.06 nM and the sensitivity of 866.23 ± 5.48, 215.82 ± 2.16, 1979.48 ± 11.47 and 204.50 ± 1.10 μA/mM for Hg(II), Cu(II), Pb(II) and Cd(II), respectively. The selectivity of the clicked-CoPc modified GCE toward Hg(II), Cu(II), Pb(II), Cd(II) present no interference from these metals ions. The fabricated electrochemical sensor exhibited very good electrochemical properties such as good reproducibility, stability, reusability and is suitable for the detection of heavy metal ions in tap water in our laboratory.

Afiliacje autorów:

Gertrude F.-other affiliation
Nwaji N.-IPPT PAN
Tebello N.-other affiliation
31.Nwaji N., John M., Tebello N., An optical limiting study in aminophenoxy substituted phthalocyanine in the presence of semiconductor quantum dots, Journal of Luminescence, ISSN: 0022-2313, Vol.203, pp.247-256, 2018

Streszczenie:

The synthesis of 4-bis(4-aminophenoxy)phenoxy derivatized phthalocyanine containing In (complex 2), and Ga
(complex 3), and the previously reported complex 4 (containing Zn) and their covalent attachment to glutathione
(GSH) functionalized cadmium telluride quantum dots (CdTe QDs) are reported in this work.
Additionally, their photophysical, energy transfer and nonlinear optical properties were investigated. The
covalently linked derivatives showed lower fluorescence quantum yields with corresponding higher triplet
quantum yields. Quenching of the photoluminescence intensity of the CdTe QDs was observed to be due to
energy transfer from the QDs to phthalocyanine (Pcs) molecules. The reverse saturable absorption nonlinear
optical response was found to be predominantly dependent on the excited state absorption. The observed limiting
threshold ranges from 0.04 to 0.62 J/cm−2.

Afiliacje autorów:

Nwaji N.-IPPT PAN
John M.-other affiliation
Tebello N.-other affiliation
32.Nwaji N., Ojodomo A., Tebello N., Photo-induced resonance energy transfer and nonlinear optical response in ball-type phthalocyanine conjugated to semiconductor and graphene quantum dots, New Journal of chemistry, ISSN: 1144-0546, DOI: 10.1039/C7NJ05196D, pp.1-13, 2018

Streszczenie:

The synthesis of ball-type zinc and gallium phthalocyanines (complexes 2 and 3) and their covalent linkage to glutathione
(GSH) and amine functionalized quantum dots (QDs) are reported in this work. Furthermore, their photophysical, photoinduced
resonance energy transfer and optical limiting response were investigated. We observed a decrease in the
fluorescence quantum yield with corresponding increase in the triplet quantum yield of the nanoconjugates in comparison
to the phthalocyanine complexes alone. The reverse saturable absorption was found to be dependent on excited state
absorption and the observed limiting threshold ranged from 0.32 to 1.43 J/cm2. Enhanced triplet parameters and
nonlinear optical performance was found when the complexes were covalently linked to semiconductor quantum dots
compared to carbon based graphene quantum dots.

Afiliacje autorów:

Nwaji N.-IPPT PAN
Ojodomo A.-other affiliation
Tebello N.-other affiliation
33.David O. O., Nwaji N., Lindokhuhle C. N., Lesedi M., Edith D., Tebello N., Novel nano-dyad of homoleptic sandwich-type phthalocyanines with nitrogen doped graphene quantum dots for nonlinear optics, New Journal of chemistry, ISSN: 1144-0546, Vol.42, pp.10124-10133, 2018

Streszczenie:

The syntheses of neodymium(III) 2,9,16,23-tetrakis-(2,6-di-tert-butyl-4-methylphenoxy)phthalocyanine (2),
bis europium(III) 2,9,16,23-tetrakis-(2,6-di-tert-butyl-4-methylphenoxy)phthalocyanine (3), bis dysprosium(III)
2,9,16,23-tetrakis-(2,6-di-tert-butyl-4-methylphenoxy)phthalocyanine (4) and their conjugated analogues with
nitrogen doped quantum dots (NGQDs) are reported herein. The optical nonlinearity of the sandwich-type phthalocyanine complexes and their conjugates with NGQDs were studied in dimethyl sulfoxide using the
open aperture Z-scan technique at an excitation wavelength of 532 nm with a 10 ns pulse. The nonlinear
absorption coefficient (beff) value of the samples ranges from 15 cm GW1 to 89.6 cm GW1
. Complex 4 and
its conjugates afforded a strong optical limiting behaviour compared to the other samples. These fabricated
complexes and their conjugates with NGQDs could serve as a plausible nonlinear optical (NLO) material due
to their fascinating NLO properties

Afiliacje autorów:

David O. O.-other affiliation
Nwaji N.-IPPT PAN
Lindokhuhle C. N.-other affiliation
Lesedi M.-other affiliation
Edith D.-other affiliation
Tebello N.-other affiliation
34.Edith D., Nwaji N., John M., Tebello N., the photophysicochemical behavior of symmetric and asymmetric zinc phthalocyanine surface assembled onto gold nanotriangles , New Journal of chemistry, ISSN: 1144-0546, DOI: 10.1039/C8NJ02746C, Vol.42, pp.14290-14299, 2018

Streszczenie:

The synthesis of a novel asymmetric phthalocyanine, (4-(4-(benzo[d]thiazol-2-yl)phenoxy)-2,10,17-tris(4-(2-carboxyethyl)phenoxy)phthalocyaninatol)zinc(II), complex 3, is reported. Complex 3 together with the previously reported complexes tetrakis[(benzo[d]thiazol-2-yl phenoxy)phthalocyaninato]zinc(II) (4) and 3-(4-((3,17,23-tris(4-(benzo[d]thiazol-2-yl)phenoxy)phthalocyaninatol)oxy)phenyl)propanoic acid zinc(II) (5), were linked to gold nanotriangles (AuNTs) through S–Au/Au–N self-assembly to afford the conjugates (3-AuNTs, 4-AuNTs and 5-AuNTs). The photophysicochemical behaviour of the complexes and their conjugates were studied. The asymmetric complexes 3 and 5, displayed improved triplet and singlet oxygen quantum yields compared to the symmetric complex 4, while all conjugates displayed improved triplet and singlet oxygen quantum yields compared to their respective complexes alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.

Afiliacje autorów:

Edith D.-other affiliation
Nwaji N.-IPPT PAN
John M.-other affiliation
Tebello N.-other affiliation
35.Nwaji N., Somila D., John M., Tebello N., Phototophysical and enhanced nonlinear optical response in asymetric benzothiazole substituted phthalocyanine covalently linked to semiconductor quantum dots, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, ISSN: 1386-1425, DOI: 10.1016/j.saa.2018.06.098, Vol.204, pp.629-639, 2018

Streszczenie:

The synthesis of asymmetric benzothiazole substituted phthalocyanines (complexes 3 to 5) and their covalent
attachment to glutathione (GSH) functionalized quantum dots (QDs) are reported in this work. Additionally,
their photophysical and nonlinear optical properties were investigated. A decrease in the fluorescence quantum
yield with corresponding increase in the triplet quantum yield was observed when the complexes were covalently
linked to glutathione (GSH) functionalized cadmiumtelluride (CdTe) quantumdots. Reverse saturable absorptionwas
found to be predominantly dominated by excited state absorption. The observed limiting threshold
values range from 0.29–0.75 J/cm2.

Afiliacje autorów:

Nwaji N.-IPPT PAN
Somila D.-other affiliation
John M.-other affiliation
Tebello N.-other affiliation
36.Edith D., David O. O., Nwaji N., Tebello N., Gylcosylated phthalocyanine-gold nanoparticles for photodynamic therapy, effect of nanoparticles shape, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, ISSN: 1386-1425, Vol.203, pp.85-95, 2018

Streszczenie:

In this work, we report on the synthesis of tris-[(2,2,7,7-tetramethyltetrahydro-3aH-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methoxy)-2-(4-benzo[d]thiazol-2-ylphenoxyphthalocyaninato] zinc(II) (complex 3) and its linkage to gold nanoparticles (AuNPs) of different shapes through S-Au/N-Au self-assembly. The conjugates of complex 3 (with both gold nanorods (AuNR) and nanospheres (AuNS)), displayed decreased fluorescence quantum yield with corresponding improved triplet and singlet quantum yields compared to complex 3 alone, however 3-AuNR showed improved properties than 3-AuNS. Complex 3 showed relatively low in vitro dark cytotoxicity against the epithelial breast cancer cells with cell survival ≥ 85% at concentration ≤ 160 μg/mL but afforded reduced photodynamic therapy activity which may be due to aggregation. 3-AuNR afforded superior PDT activity with <50% viable cells at concentration ≥ 40 μg/mL in comparison to 3-AuNS with <50% viable cells at concentration ≥ 80 μg/mL. The superior activity of 3-AuNR is attributed to the photothermal therapy effect since nanorods absorb more light at 680 nm than nanospheres

Afiliacje autorów:

Edith D.-other affiliation
David O. O.-other affiliation
Nwaji N.-IPPT PAN
Tebello N.-other affiliation
37.Nwaji N., John M., Tebello N., Photophysical and strong optical limiting properties of ball-type phthalocyanines dimers and their monomeric analogues, Journal of Photochemistry and Photobiology A, ISSN: 1010-6030, DOI: 10.1016/j.jphotochem.2017.10.045, Vol.352, pp.73-85, 2018

Streszczenie:

The nonlinear optical behaviors of ball-type phthalocyanine complexes: 10,11,’150,250-tetrakis-[4,40-((4-
formyl-1,2-bisphenoxyl))bis(phthalocyaninato zinc (II)] (5), 10,11,’150,250-tetrakis-[4,40-((4-formyl-1,2-
bisphenoxyl) bis(phthalocyaninato gallium (III) chloride)] (6), and 10, 11,’150,250-tetrakis-4,40-((4-formyl-
1,2-phenoxyl)bis(phthalocyaninato indium (III) chloride)] (7) and the corresponding monomeric
derivatives 8–10 were investigated using nanosecond pulse open aperture Z-scan technique at
532 nm. The nonlinear response showed strong reverse saturable absorption for all the complexes both in
solution and when embedded in polymer matrix. The dimeric complexes showed better optical limiting
properties compared to the monomeric derivatives. The beff values for the dimeric complexes 5–7 were
found to be 48.5, 55.2, and 60.1 cm/GW for 5, 6A, and 7 respectively, higher than the corresponding
monomeric derivatives 8–10. Enhanced optical limiting properties were observed when the complexes
were formulated in thin
films. The second order hyperpolarizability values were in order of 1028–
1026 esu in solution and 1027–1026 in
films.

Afiliacje autorów:

Nwaji N.-IPPT PAN
John M.-other affiliation
Tebello N.-other affiliation
38.Refilwe M., Nwaji N., Muthumuni M., Earl P., Tebello N., Effect of number of positive charges on the photophysical and photodynamic therapy activities of quarternary benzothiazole substituted zinc phthalocyanine, Journal of Photochemistry and Photobiology A, ISSN: 1010-6030, Vol.367, pp.253-260, 2018

Streszczenie:

The synthesis, photophysicochemical and photodynamic therapy (PDT) activity of quaternary benzothiazole substituted zinc phthalocyanine (2, containing two charges, and 3, containing four charges) are reported in this work. Furthermore, the activity of the synthesized complex was compared to non-quaternary derivative (1). Higher triplet and singlet oxygen quantum yields of 0.92 and 0.85, respectively, for quaternized complexes 2 and 3 compared to complex 1 alone. Complexes 1, 2 and 3 showed relatively no dark toxicity against the epithelial breast cancer cells with cell survival of above 90 ± 3%. The quaternary derivatives (2 and 3) showed superior PDT activity with 30% or less of viable cells at concentration of 50.0 μg/mL in comparison to complex 1 alone which further lay credence to the importance of quaternization in the enhancement of PDT activit

Afiliacje autorów:

Refilwe M.-other affiliation
Nwaji N.-IPPT PAN
Muthumuni M.-other affiliation
Earl P.-other affiliation
Tebello N.-other affiliation
39.Bokolombe P. N., Zweli H., Nwaji N., Gertrude F., John M., Tebello N., Photophysical and optical limiting properties at 532 nm of BODIPY dyes with p-benzyloxystyryl groups at the 3,5-positions, Journal of Porphyrins and Phthalocyanines, ISSN: 1088-4246, DOI: 10.1142/S1088424617500857, Vol.22, pp.413-422, 2018

Streszczenie:

The synthesis and characterization of a series of 3,5-di-p
-benzyloxystyrylBODIPY dyes with different substituents at the meso-aryl position is reported. The photophysical and nonlinear optical properties are described. BODIPYs of this type are found to be suitable for optical limiting at 532 nm on the nanosecond timescale. An enhancement of the population of the T1
state through the incorporation of bromine atoms at the 2,6-positions does not result in an enhancement of the optical limiting properties on a nanosecond timescale. This suggests that, in contrast with phthalocyanines, access to excited state absorption (ESA) from the T1
state through the introduction of a heavy atom effect does not provide a significantly improved reverse saturable absorbance response compared to ESA from the S1
state.

Afiliacje autorów:

Bokolombe P. N.-other affiliation
Zweli H.-other affiliation
Nwaji N.-other affiliation
Gertrude F.-other affiliation
John M.-other affiliation
Tebello N.-other affiliation
40.Omaka N. O., Anthony C. E., Nwaji Njemuwa N., Damian C. O., Nickel(II) and copper(II) complexes of 2,2‐bibenzo[d] thiazole: Synthesis, characterisation and biological studies , Applied Organometallic Chemistry, ISSN: 1099-0739, DOI: 10.1002/aoc.4241, Vol.32, pp.1-10, 2018

Streszczenie:

Benzothiazole moiety has gained a lot of attention because of its importance as essential pharmacophore in the development of metal based drugs. Nickel(II) and copper(II) complexes of a benzothiazole based ligand, 2,2’-bibenzo[d]thiazole (L1), synthesized by the reaction of benzothiazole-2-carbonylchloride and o-aminothiophenol, is reported. The compounds were characterised by elemental and percentage metal analyses, spectroscopic (FTIR and UV–vis), 1H and 13C NMR, Mass spectra, thermal, magnetic moment and molar conductance analyses. The mass spectra, elemental and percentage metal composition of the metal complexes gave a 2:1 ligand to metal stoichiometric mole ratio. The spectral data showed that the ligand was coordinated to the metal ions through the nitrogen atoms of the benzothiazole moiety. The electronic spectra and magnetic susceptibility measurements showed that the nickel and copper complexes adopted square planar geometries. The ligand and its metal(II) complexes were screened against some drug resistant microbes and were found to exhibit varied degree of antimicrobial activities. The nickel complex was more active compared to ciprofloxacin against Staphylococcus aureus and Bacillus cereus. Similarly, the antioxidant potential of the ligand was evaluated. The ligand is a better ferrous ion chelating agent compared to 1,10-phenanthroline and 2,2-bipyridine. The ligand and its complexes exhibited good antimicrobial and Fe2+ chelating properties making them probable compounds of interest in antibiotic and antioxidant drug researches.

Afiliacje autorów:

Omaka N. O.-other affiliation
Anthony C. E.-other affiliation
Nwaji Njemuwa N.-IPPT PAN
Damian C. O.-other affiliation
41.Nwaji N., Tebello N., Nanosecond optical nonlinearities in low symmetry phthalocyanine nanoconjugates studied using the Z- scan technique, Journal of Luminescence, ISSN: 0022-2313, DOI: 10.1016/j.jlumin.2017.08.053, Vol.192, pp.247-256, 2017

Streszczenie:

In this study, the photophysical, and nonlinear optical limiting properties of low symmetry tris[(4-benzo[d] thiazol-2-ylphenoxy)-2-phenoxyl acetic acid phthalocyaninato] zinc (II) (3) conjugated to metallic nanoparticles have been investigated using open aperture Z-scan techniques at 532 nm. The nonlinear optical response demonstrated that the studied complex and the nanoconjugates exhibits higher excited state absorption cross-section resulting from S1 and T1 compared to ground state absorption. Enhanced optical limiting performance was observed when the complex was conjugated to nanoparticles with 3SA-AuNPs showing the best optical limiting threshold of 0.39 J/cm2.

Afiliacje autorów:

Nwaji N.-IPPT PAN
Tebello N.-other affiliation
42.Nwaji N., John M., Jonathan B., Tebello N., Synthesis, photophysical and nonlinear optical properties of a series of ball-type phthalocyanines in solution and thin films, New Journal of chemistry, ISSN: 1144-0546, DOI: 10.1039/C6NJ03662G, Vol.41, pp.1-15, 2017

Streszczenie:

In this study, we report on the enhanced nonlinear optical properties of novel tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato zinc(II)) (4), tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato gallium chloride) (5) and tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato indium chloride) (6) both in solution and when embedded in polymer thin films. Complexes 5 and 6 bearing heavy atoms showed enhanced triplet quantum yield and nonlinear optical response. The nonlinear third-order susceptibility and second-order hyperpolarizability values are also reported. Time dependent density functional theory (TD-DFT) calculations were performed in order to explain the origin of the observed UV-vis and magnetic circular dichroism (MCD) spectra of the complexes.

Afiliacje autorów:

Nwaji N.-IPPT PAN
John M.-other affiliation
Jonathan B.-other affiliation
Tebello N.-other affiliation
43.Nwaji N., John M., Tebello N., 4-Bis (4-aminophenoxy)phenoxy derivitized phthalocyanine conjugated to metallic nanoparticles: searching for enhanced optical limiting materials, New Journal of chemistry, ISSN: 1144-0546, DOI: 10.1039/C7NJ02718D, Vol.41, pp.1-15, 2017

Streszczenie:

n this study, the photophysical, nonlinear absorption and nonlinear optical limiting properties of 4-(2,4-bis(4-aminophenoxy)phenoxy) phthalocyinato zinc(II) phthalocyanine (6) conjugated to metallic nanoparticles have been investigated using open aperture Z-scan techniques using 532 nm nanosecond pulses. The nonlinear optical response demonstrated that the studied complex and the nanoconjugates exhibit higher excited state absorption cross-section compared to ground state absorption. Enhanced optical limiting performance was observed when complex 6 was conjugated to nanoparticles with 6CB-AuNPs (CB = covalent bond) showing the highest optical limiting threshold of 0.36 J cm−2.

Afiliacje autorów:

Nwaji N.-IPPT PAN
John M.-other affiliation
Tebello N.-other affiliation
44.Nwaji N., Benjamin J., John M., David O. O., Tebello N., Nonlinear optical dynamics of benzothiazole derivatized phthalocyanines in solution, thin films and when conjugated to nanoparticles, Journal of Photochemistry and Photobiology A, ISSN: 1010-6030, DOI: 10.1016/j.jphotochem.2017.05.042, Vol.346, pp.73-85, 2017

Streszczenie:

Benzothiazole phthalocynines complexes: tetrakis[(benzo[d]thiazol-2-ylphenoxy)phthalocyaninato] indium(III) chloride (1) and tetrakis[(benzo[d]thiazol-2-ylthio)phthalocyaninato] indium(III) chloride (2) were synthesisized and their nanosecond nonlinear optical behaviours in solution, solid state and when conjugated to metallic nanoparticles were examined and compared to those of the corresponding ZnPc and GaPc which are designated as: tetrakis[(4-benzo[d]thiazol-2-ylphenoxy)phthalocyaninato] zinc(II) (3), tetrakis[(4-benzo[d]thiazol-2-ylphenoxy)phthalocyaninato] gallium(III) chloride (4), tetrakis[(4-benzo[d]thiazol-2-ylthio)phthalocyaninato] zinc(II) (5) and tetrakis[(4-benzo[d]thiazol-2-ylthio)phthalocyaninato] gallium(III) chloride (6). Trends in the electronic structures were identified through a comparison of the UV–vis absorption and magnetic circular dichroism (MCD) spectroscopy of the complexes and calculated spectra predicted by time dependent density functional theory (TD-DFT). Of all the complexes and nanoconjugates, complex 2 (containing sulphur linkages and In as a central metal) gave the best optical limiting behaviour.

Afiliacje autorów:

Nwaji N.-IPPT PAN
Benjamin J.-other affiliation
John M.-other affiliation
David O. O.-other affiliation
Tebello N.-other affiliation
45.Edith D., Nwaji N., David O. O., John M., Tebello N., Investigation of photophysicochemical properties of zinc phthalocyanines conjugated to metallic nanoparticles , Journal of Photochemistry and Photobiology A, ISSN: 1010-6030, DOI: 10.1016/j.jphotochem.2017.09.020, Vol.349, pp.148-161, 2017

Streszczenie:

The syntheses of zinc(II) tetra–[3–(4–phenoxy) (propanoic acid) phthalocyanine] (2) and zinc(II) mono–[3–(4–phenoxy) (propanoic acid) phthalocyanine (3) are reported in this work. Compounds 2 and 3 were covalently linked to glutathione capped silver (AgNPs–GSH), gold (AuNPs–GSH) and silver-gold alloy (Ag3Au1NPs–GSH) nanoparticles (NPs) via an amide bond formation to afford the conjugates: 2–AgNPs–GSH, 3–AgNPs–GSH, 2–AuNPs–GSH, 3–AuNPs–GSH, 2-Ag3Au1NPs–GSH and 3-Ag3Au1NPs–GSH. The photophysicochemical behaviours of the compounds and their conjugates with NPs were assessed in solution. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet quantum yields in comparison to the compounds. Accordingly, the AgNPs and AuNPs conjugates with the compounds afforded high singlet quantum yields. On the contrary, the conjugates of the alloy afforded decreased singlet quantum yields probably due to the screening effect. The compounds and their conjugates with NPs could serve as a viable and efficacious photosensitizer for photodynamic therapy.

Afiliacje autorów:

Edith D.-other affiliation
Nwaji N.-IPPT PAN
David O. O.-other affiliation
John M.-other affiliation
Tebello N.-other affiliation
46.Nwaji N., Owolabi M. B., Jonathan B., Tebello N., Photophysical and nonlinear optical study of benzothiazole substituted phthalocyanines in solution and thin films , Journal of Porphyrins and Phthalocyanines, ISSN: 1088-4246, DOI: 10.1142/S1088424617500079, Vol.21, pp.1-10, 2017

Streszczenie:

In this study, the photophysical, nonlinear absorption and nonlinear optical limiting properties of zinc and gallium phthalocyanine complexes: tetrakis[(benzo[d]thiazol-2-yl phenoxy)phthalocyaninato]zinc(II) (3), tetrakis[(benzo[d]thiazol-2-yl phenoxy)phthalocyaninato] gallium(III) chloride (4), tetrakis[(benzo[d]thiazol-2-ylthio)phthalocyaninato] zinc(II) (5), tetrakis[(benzo[d]thiazol-2-ylthio)phthalocyaninato] gallium(III) chloride (6), were investigated both in solution and when embedded in polystyrene thin films using 532 nm laser excitation at 10 ns pulses. It was also observed that complexes that have higher triplet state absorption also possessed enhanced nonlinear and optical limiting behavior. Superior optical performance was observed when the complexes were embedded in thin films compared to when they are in solution. Complex 6 in thin films gave the highest imaginary third-order susceptibility (Im
[X(3)]) and hyperpolarizability (γ) at 4.61 × 10-7
esu and 3.44 × 10-26 esu, respectively, with a low Ilim value of 0.06 J.cm-2

Afiliacje autorów:

Nwaji N.-IPPT PAN
Owolabi M. B.-other affiliation
Jonathan B.-other affiliation
Tebello N.-other affiliation
47.Nwaji N., David O. O., John M., Marcel L., Samson K., Jonathan B., Tebello N., Improved nonlinear optical behaviour of ball type indium (III) phthalocyanine linked to glutathione capped nanoparticles, Dyes and Pigments, ISSN: 1873-3743, DOI: 10.1016/j.dyepig.2017.01.066, Vol.140, pp.417-430, 2017

Streszczenie:

The synthesis of ball–type indium phthalocyanine (complex 4) and its covalent attachment to glutathione (GSH–) capped (Ag, Au, CdTeSe, CdTeSe/ZnO) nanoparticles are reported in this work. Furthermore, their photophysical and nonlinear optical behaviour were investigated. We observed a decrease in the fluorescence quantum yield with corresponding increase in the triplet quantum yield of the nanoconjugates in comparison to complex 4 alone. The reverse saturable absorption was found to be dependent on excited state absorption. The optical limiting threshold ranges from 0.40–0.78 (J/cm2). The nanoconjugate of the complex 4 with GSH–CdTeSe/ZnO (QD1) accounted for the most improved triplet state parameters and nonlinear optical behaviour in comparison to complex 4 and the other nanoconjugates studied in this work.

Afiliacje autorów:

Nwaji N.-IPPT PAN
David O. O.-other affiliation
John M.-other affiliation
Marcel L.-other affiliation
Samson K.-other affiliation
Jonathan B.-other affiliation
Tebello N.-other affiliation

Abstrakty konferencyjne
1.Nwaji N., Achadu O., Giersig M., Porous magnetic nanostructures for sensing SARS-CoV-2, AMBRA 2024, 2nd International Conference on Advanced Materials for Bio-Related Applications , 2024-05-19/05-23, Wrocław (PL), pp.50, 2024