Abstract
The development of efficient electrocatalyst to produce molecular hydrogen from water is receiving considerable attention, in an effort to decrease our reliance on fossil fuels. The prevention of the aggregation of active sites during material synthesis, in order to increase charge transport properties of electrocatalysts, is needed. We have designed, synthesized, and studied a Ag2S/reduced graphene oxide (rGO) electrochemical catalyst (for hydrogen evolution) from water. The Ag2S nanocrystals were synthesized by the solvothermal method in which the rGO was added. The addition of the rGO resulted in the formation of smaller Ag2S nanocrystals, which consequently increased the electrical conductivity of the composite catalyst. The composite catalyst showed a higher electrochemical catalytic activity than the one with an absence of rGO. At a current density of 10 mA/cm(2), a low overpotential of 120 mV was obtained. A Tafel slope of 49.1 mV/dec suggests a Volmer-Herovsky mechanism for the composite catalyst. These results may provide a novel strategy for developing hydrogen evolution reaction (HER) electrocatalysts, via the combining of a nano-semiconductor catalyst with a 2D material.