Systematic Mapping of Electrocatalytic Descriptors for Hybrid and Non-Hybrid Molybdenum Dichalcogenides with Graphene Support for Cathodic Hydrogen Generation

Abstract

For the hydrogen evolution reaction (HER) from water electrolysis, electrocatalytic performances of nanocomposites consisting of hybrid and non-hybrid molybdenum dichalcogenides with graphene (MoCh 2 /Gr) support (MoS 2 /Gr, MoSe 2 /Gr, MoTe 2 /Gr, MoSSe/Gr, MoSTe/Gr, MoSeTe/Gr, and MoS 0.67 Se 0.67 Te 0.67 /Gr) have been investigated both computationally and experimentally. In the computational part, hydrogen binding energetics of various adsorption sites on hybrid and non-hybrid MoCh 2 /Gr are elucidated with plane-wave density functional theory to evaluate the catalytic performance according to Sabatier's principle. Near-zero values of Gibbs free energy of binding (ΔG b ≈ 0) have been considered a criterion for establishing the most catalytically active site. Moreover, electrochemical measurements revealed that all the materials, which have been synthesized through a microwave-assisted heating approach, are highly active and durable for the HER with overpotentials in the range of 127− 217 mV and have negligible activity loss for 96 h of constant potential tests. Among all the different molybdenum dichalcogenide/ graphene nanocomposites, the materials containing a high (≥50%) stoichiometric proportion of tellurium (Te) exhibited better HER activities compared to other chalcogens. Most importantly, hybrid nanocomposites, except the highest-entropy alloy MoS 0.67 Se 0.67 Te 0.67 /Gr, exhibited improved performance compared to the non-hybrid MoCh 2 compounds.

Introduction of MoS2–FeS2 with an S-Vacancy Defect as an Efficient Bifunctional Electrocatalyst for Hydrogen Evolution Reaction and Ferrocyanide and Iodide Oxidation Reactions

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“…Among the various research areas in energy systems, hydrogen gas production and storage stand out as particularly promising. 1 With its high gravimetric energy density, approximately three times that of common fossil fuels, hydrogen has emerged as a green fuel option with zero carbon emissions. Its production from diverse resources such as natural gas, biogas, and renewable sources like solar and wind underscores its versatility.…”