Partner: Kang Hyojin


Recent publications
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: doi.org/10.1002/cssc.202400395, pp.2-9, 2024
Abstract:

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
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
Abstract:

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.

Keywords:

imaging, metasurfaces, quantum dots, sensing, terahertz

Affiliations:
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)
3.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
Abstract:

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.

Affiliations:
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)
4.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
Abstract:

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.

Keywords:

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

Affiliations:
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)
5.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
Abstract:

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.

Affiliations:
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)