The search for efficient and practically applicable electrocatalysts to sustainably produce hydrogen has become more critical than ever. In recent years, transition metal chalcogenides with an electrically conductive support material in the form of a composite have garnered interest as hydrogen evolution reaction (HER) catalysts due to their unique electronic, mechanical, and electrochemical properties. An approach to gain insight into the important descriptors for catalytic performance which are difficult to measure experimentally is periodic plane-wave density functional theory (DFT) calculations. In this study, plane-wave DFT calculations have been performed to probe the hydrogen binding energetics of various adsorption sites on hybrid molybdenum chalcogenides/graphene nanocomposites to evaluate catalytic performance. Conventionally, Gibbs free energy of hydrogen binding (ΔGb) values for good catalytically active sites are considered within the range of -0.2 eV and 0.2eV. All composite HER catalyst systems that have been considered in this computational investigation have binding sites within this range. Moreover, using the calculated binding free energy (ΔGb) and the experimentally measured current density (i0), a volcano plot has been generated where the molybdenum hybrid chalcogenide/graphene nanocomposite has been found to be near the apex of the volcano close to Pt performance. The high performance of the molybdenum hybrid chalcogenide with graphene support in this study shows the future potential for practical application and commercialization.

Enhancement of electrocatalytic hydrogen evolution reaction using noble metal free hybrid molybdenum chalcogenide/graphene nanocomposites: A combined computational and experimental investigation

ACS Fall 2021

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