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Author: search.filters.author.Hegde, A.P.Subject: search.filters.subject.Hydrogen evolution reactions

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    Cerium doping of FeS2 for the effective hydrogen evolution reaction (HER) electrocatalysis
    (Taylor and Francis Ltd., 2025) Hegde, A.P.; Gonde, A.; Kumawat, A.; Mukesh, P.; Lakshmisagar, G.; Kumar, A.; Nagaraja, H.S.
    Crafting and developing nanostructured electrocatalyst materials that are both active and stable plays a pivotal role in the shift toward economically viable hydrogen production through electrochemical water splitting, paving the way for the future replacement of fossil fuels. Such materials need to be cost-effective, simple to produce, and durable. In this context, the current research delves into improving the hydrogen evolution reaction (HER) electrocatalytic performance by incorporating cerium (Ce) into iron disulfide (FeS2) catalysts, using an uncomplicated hydrothermal fabrication approach. The study systematically examines the effects of various Ce doping levels on electrocatalytic activity. Notably, the catalyst with 15% Ce doping demonstrated exceptional efficiency, reducing the overpotential to 369 mV at 100 mA cm?2 current density. This enhanced performance can be attributed to the reduction in total charge-transfer resistance and a significant increase in the electrochemical active surface area (ECSA). Furthermore, the durability assessment of the 15% Ce-doped sample revealed its ability to sustain its catalytic activity for over 100 h under a continuous HER operation at 300 mA cm-2, with low performance-falloff. These results highlight the potential of Ce-dopping of FeS2 catalysts as a formidable choice for achieving efficient and long lasting HER electrocatalysis. © 2025 Taylor & Francis Group, LLC.
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    Ag2Cu2O3 Nanorods as Electrocatalysts for Hydrogen Production and Overall Water Splitting
    (American Chemical Society, 2025) Kumar, A.; Hegde, A.P.; Puttur, M.; Gangadharappa, L.S.; Hosakoppa, N.S.
    In this research, a series of Ag2Cu2O3 nanorods as electrocatalysts were prepared with three different drying temperatures (namely, W - 50, W - 80, and W - 120), utilizing a regular coprecipitation approach. These nanorods’ surface morphology and structural attributes were thoroughly characterized using Field Emission Scanning Electron Microscopy and High-Resolution Transmission Electron Microscopy, while X-ray diffraction provided insight into their crystal structures. The compositional analysis was accomplished via X-ray photoelectron spectroscopy and Raman spectroscopy. The W - 50 catalyst exhibited the most promising electrochemical response among the synthesized samples. In the solution of 1 M KOH, at a current density of 10 mA cm-2, it demonstrated modest overpotential values and Tafel slopes of 81 and 97 mV dec-1 for the hydrogen evolution reaction (HER), whereas 409 and 140 mV dec-1 for the oxygen evolution reaction (OER). When tested with a two-electrode electrolyzer, W - 50 serving as together the anode and cathode, a trivial cell voltage of 1.9842 V was required to accomplish a current density of 100 mA cm-2, with surprising stability over 50 h of continuous operation at 200 mA cm-2 for overall water splitting. Additionally, W - 50 displayed excellent performance for HER; it necessitated an overpotential of 337 mV to accomplish an extreme current density of 800 mA cm-2. This inquiry provides precious perceptions into the importance of confined spaces within transition metal oxide-based catalysts, advancing their application in electrocatalysis. © 2025 American Chemical Society.
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    Melamine – Ni-MIL-88A blend derived Trevorite/C-g-C3N4 for stable and efficient overall electrocatalytic water splitting applications
    (Elsevier Ltd, 2025) Hegde, A.P.; P, M.; G, L.; Kumar, A.; Nagaraja, H.S.
    The electrocatalytic splitting of water into hydrogen and oxygen plays a pivotal role in addressing the energy demands associated with expanding anthropogenic activities. The design of economically feasible and effective electrocatalytic materials for water electrolysis is imperative for the sustainable production of hydrogen and oxygen. In this context, this study introduces an electrocatalyst design comprising graphitic carbon nitride (g-C3N4) and Trevorite (Ni(Ni, Fe)2O4) synthesized through the pyrolysis of a mixture Ni-substituted metal–organic framework (MOF) MIL-88A and of melamine. The synthesized material was evaluated as an electrocatalyst for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). The nickel foam coated with this electrocatalyst exhibits a performance characterized by lower overpotentials of 121 mV for HER and 231 mV for OER at a current density of 10 mA cm-2 in an alkaline medium of 1 M KOH. Furthermore, the composite demonstrated an excellent overall water splitting capacity, maintaining a high current density of 500 mA cm-2 for more than 50 h of continuous electrolysis in 1 M KOH solution with a minimal voltage increase of approximately 0.025 V. © 2025