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, 2024Abstract: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 Keywords:Hydrogen production, inverse opals, perovskite, quantum dots, photocatalysts, photonic crystals Affiliations: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 |
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2. | 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, 2024Abstract: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 Affiliations: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) |
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3. | 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, 2024Abstract: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. Affiliations: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 |
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4. | 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, 2024Abstract: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. Keywords:electrodeposition, hydrogen evolution reactions, catalytic activity, Cu/MoS2 nanostructures Affiliations: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 |
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5. | 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, 2024Abstract: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. Keywords:Electrocatalyst, Double layered hydroxide, oxygen evolution reaction, oxygen vacancy, stabilization Affiliations: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) |
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6. | 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, 2023Abstract: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. Affiliations: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) |
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7. | 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, 2023Abstract: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. Affiliations: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) |
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