Ag 2 S/Ag Heterostructure: A Promising Electrocatalyst for the Hydrogen Evolution Reaction.

Different metal chalcogenides, being a potential candidate for hydrogen evolution catalysts, have attracted enormous attention in the field of water splitting. In the present study, Ag2 S/Ag is revealed as an efficient catalyst for hydrogen evolution. When a sacrificial template of the CuS nanostructure is used, Ag2 S/Ag heterostructures are synthesized following a simple wet-chemical technique. Two different routes, wet chemical and hydrothermal, are followed to modulate the morphology of the CuS templates from flower ball to wirelike structures, which subsequently results in the formation of Ag2 S nanostructure. Finally, the Ag layer is deposited on Ag2 S with the help of a photoreduction technique. The unique heterostructure of Ag2 S/Ag shows efficient catalytic activity in the H2 evolution reaction. A Ag2 S/Ag wire can successfully generate a 10 mA/cm2 current density at a -0.199 V potential. Ag2 S/Ag contains the micronanostructure where nanoplates of Ag2 S/Ag assemble to give rise to microstructures such as flower balls and wire.