Amorphous MoWS _x Alloy Nanosheets via Room-Temperature Precipitation Method for Enhanced Electrocatalytic Hydrogen Evolution Reactions

Development of highly active, stable, and noble-metal-free electrocatalysts holds great promise for efficient production of hydrogen through water electrolysis. Transition metal dichalcogenides (TMDs) have been well-explored as a highly efficient and stable electrocatalyst for the hydrogen evolution reaction (HER). One of the ongoing challenges is to activate inert basal planes and improve conductivity of TMDs to realize efficient HER, but that requires laborious and time-consuming chemical strategies utilizing high-temperature treatment methods. Herein, we developed a simple precursor-solution-aging assisted acid induced precipitation method without any external energy to fabricate highly active amorphous MoWS x alloy nanosheets of varying composites for electrocatalytic HER. Among the various amorphous MoWS x composites, Mo0.5W0.5S x hybridized with carbon support (Mo0.5W0.5S x /C) catalyst revealed superior activity (eta = 170 mV at 10 mA cm-2) than the other composite catalysts, including the individual amorphous MoS x /C and WS x /C counterparts. When assembled as an electrolyzer, Mo0.5W0.5S x /C required only a cell voltage of 1.65 V to attain 10 mA cm-2 for overall water splitting and exhibited remarkable stability for more than 24 h. This simple strategy for the rational design of highly efficient MoWS x alloy electrocatalysts for water splitting can also be explored for other TMD-type catalysts for industrial and fundamental applications.