Siyabonga Nkabinde - Academia.edu (original) (raw)
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Papers by Siyabonga Nkabinde
Arabian Journal of Chemistry, 2022
SSRN Electronic Journal, 2021
The synthesis of non-noble metal nanocrystals as cheaper alternatives to Pt for use as hydrogen e... more The synthesis of non-noble metal nanocrystals as cheaper alternatives to Pt for use as hydrogen evolution reaction (HER) electrocatalysts is highly desired for the future of renewable energy. In this work, amorphous molybdenum phosphide (MoP) nanocrystals were synthesized via the colloidal synthesis by heating MoCl5 (Mo source), 1-octadecene (solvent and reducing agent) and trioctylphosphine (P source) at 340 °C for 6 h. Subsequently, the amorphous nanocrystals were converted into crystalline nanocrystals through annealing. Broad XRD peaks in conjunction with diffuse rings in the SAED pattern confirmed the amorphous nature of the as-synthesized nanocrystals. Alternatively, sharp XRD peaks and spotty diffraction rings in the SAED pattern confirmed the crystalline nature of the annealed nanocrystals. The amorphous nanocrystals were small, highly dispersed and had a semi-spherical morphology. The annealed nanocrystals retained their dispersity and semi-spherical morphology but increase...
A dissertation submitted in fulfilment of the requirements for the degree of Master of science in... more A dissertation submitted in fulfilment of the requirements for the degree of Master of science in the school of Chemistry faculty of science University of the Witwatersrand March 2018
1-alkanethiol SAMs on AuNPs have shown great potential towards the development of new functional ... more 1-alkanethiol SAMs on AuNPs have shown great potential towards the development of new functional materials. This is mainly due to the formation of dense, tightly bonded and well-ordered systems on the surface of AuNPs. This work showcases how the chain-length of 1-alkanethiols affects the stability and surface properties of AuNPs and the SERS effect. Using experimental and theoretical studies (by means of DFT), this work shows the interaction between 1-alkanethiols of 3 different chain-lengths and AuNPs. The effects on the optical properties, surface charge, stability and SERS were also investigated. The red shift of surface plasmon resonance band was observed as a result of the interaction between AuNPs and 1-alkanethioals. The Zeta potential indicated a strong electrostatic repulsion between AuNPs which was reduced after functionalizing with 1-alkanethiols. The long chain alkanethiol was found to strongly reduce the surface charge due to strong interaction with AuNPs. The calculat...
New Journal of Chemistry
Transition metal phosphides (TMPs) have emerged as efficient non-noble electrocatalysts for hydro... more Transition metal phosphides (TMPs) have emerged as efficient non-noble electrocatalysts for hydrogen evolution reaction (HER).
Nanomaterials
Herein we report on the use of different metal precursors in the synthesis of MoSe2 nanomaterials... more Herein we report on the use of different metal precursors in the synthesis of MoSe2 nanomaterials in order to control their morphology. The use of Mo(CO)6 as the metal precursor resulted in the formation of wrinkled few-layer nanosheets, while the use of H2MoO4 as the metal precursor resulted in the formation of nanoflowers. To investigate the effect of the morphologies on their performance as catalysts in the hydrogen evolution reaction, electrochemical characterization was done using linear sweep voltammetry (LSV), cyclic voltammetry (CV), and electrical impedance spectroscopy (EIS). The MoSe2 nanoflowers were found to have superior electrochemical performance towards the hydrogen evolution reaction with a lower Tafel slope, on-set potential, and overpotential at 10 mA/cm2 compared to the wrinkled few-layer nanosheets. This was found to be due to the higher effective electrochemical surface area of the nanoflowers compared to the nanosheets which suggests a higher number of expose...
Nanomaterials
Herein we report on the use of different metal precursors in the synthesis of MoSe2 nanomaterials... more Herein we report on the use of different metal precursors in the synthesis of MoSe2 nanomaterials in order to control their morphology. The use of Mo(CO)6 as the metal precursor resulted in the formation of wrinkled few-layer nanosheets, while the use of H2MoO4 as the metal precursor resulted in the formation of nanoflowers. To investigate the effect of the morphologies on their performance as catalysts in the hydrogen evolution reaction, electrochemical characterization was done using linear sweep voltammetry (LSV), cyclic voltammetry (CV), and electrical impedance spectroscopy (EIS). The MoSe2 nanoflowers were found to have superior electrochemical performance towards the hydrogen evolution reaction with a lower Tafel slope, on-set potential, and overpotential at 10 mA/cm2 compared to the wrinkled few-layer nanosheets. This was found to be due to the higher effective electrochemical surface area of the nanoflowers compared to the nanosheets which suggests a higher number of expose...
Arabian Journal of Chemistry, 2022
SSRN Electronic Journal, 2021
The synthesis of non-noble metal nanocrystals as cheaper alternatives to Pt for use as hydrogen e... more The synthesis of non-noble metal nanocrystals as cheaper alternatives to Pt for use as hydrogen evolution reaction (HER) electrocatalysts is highly desired for the future of renewable energy. In this work, amorphous molybdenum phosphide (MoP) nanocrystals were synthesized via the colloidal synthesis by heating MoCl5 (Mo source), 1-octadecene (solvent and reducing agent) and trioctylphosphine (P source) at 340 °C for 6 h. Subsequently, the amorphous nanocrystals were converted into crystalline nanocrystals through annealing. Broad XRD peaks in conjunction with diffuse rings in the SAED pattern confirmed the amorphous nature of the as-synthesized nanocrystals. Alternatively, sharp XRD peaks and spotty diffraction rings in the SAED pattern confirmed the crystalline nature of the annealed nanocrystals. The amorphous nanocrystals were small, highly dispersed and had a semi-spherical morphology. The annealed nanocrystals retained their dispersity and semi-spherical morphology but increase...
A dissertation submitted in fulfilment of the requirements for the degree of Master of science in... more A dissertation submitted in fulfilment of the requirements for the degree of Master of science in the school of Chemistry faculty of science University of the Witwatersrand March 2018
1-alkanethiol SAMs on AuNPs have shown great potential towards the development of new functional ... more 1-alkanethiol SAMs on AuNPs have shown great potential towards the development of new functional materials. This is mainly due to the formation of dense, tightly bonded and well-ordered systems on the surface of AuNPs. This work showcases how the chain-length of 1-alkanethiols affects the stability and surface properties of AuNPs and the SERS effect. Using experimental and theoretical studies (by means of DFT), this work shows the interaction between 1-alkanethiols of 3 different chain-lengths and AuNPs. The effects on the optical properties, surface charge, stability and SERS were also investigated. The red shift of surface plasmon resonance band was observed as a result of the interaction between AuNPs and 1-alkanethioals. The Zeta potential indicated a strong electrostatic repulsion between AuNPs which was reduced after functionalizing with 1-alkanethiols. The long chain alkanethiol was found to strongly reduce the surface charge due to strong interaction with AuNPs. The calculat...
New Journal of Chemistry
Transition metal phosphides (TMPs) have emerged as efficient non-noble electrocatalysts for hydro... more Transition metal phosphides (TMPs) have emerged as efficient non-noble electrocatalysts for hydrogen evolution reaction (HER).
Nanomaterials
Herein we report on the use of different metal precursors in the synthesis of MoSe2 nanomaterials... more Herein we report on the use of different metal precursors in the synthesis of MoSe2 nanomaterials in order to control their morphology. The use of Mo(CO)6 as the metal precursor resulted in the formation of wrinkled few-layer nanosheets, while the use of H2MoO4 as the metal precursor resulted in the formation of nanoflowers. To investigate the effect of the morphologies on their performance as catalysts in the hydrogen evolution reaction, electrochemical characterization was done using linear sweep voltammetry (LSV), cyclic voltammetry (CV), and electrical impedance spectroscopy (EIS). The MoSe2 nanoflowers were found to have superior electrochemical performance towards the hydrogen evolution reaction with a lower Tafel slope, on-set potential, and overpotential at 10 mA/cm2 compared to the wrinkled few-layer nanosheets. This was found to be due to the higher effective electrochemical surface area of the nanoflowers compared to the nanosheets which suggests a higher number of expose...
Nanomaterials
Herein we report on the use of different metal precursors in the synthesis of MoSe2 nanomaterials... more Herein we report on the use of different metal precursors in the synthesis of MoSe2 nanomaterials in order to control their morphology. The use of Mo(CO)6 as the metal precursor resulted in the formation of wrinkled few-layer nanosheets, while the use of H2MoO4 as the metal precursor resulted in the formation of nanoflowers. To investigate the effect of the morphologies on their performance as catalysts in the hydrogen evolution reaction, electrochemical characterization was done using linear sweep voltammetry (LSV), cyclic voltammetry (CV), and electrical impedance spectroscopy (EIS). The MoSe2 nanoflowers were found to have superior electrochemical performance towards the hydrogen evolution reaction with a lower Tafel slope, on-set potential, and overpotential at 10 mA/cm2 compared to the wrinkled few-layer nanosheets. This was found to be due to the higher effective electrochemical surface area of the nanoflowers compared to the nanosheets which suggests a higher number of expose...