First-principles study on the Cu-Au alloy monolayer supported on WC for hydrogen evolution

Rational design of supported catalysts with alloy monolayer on suitable substrate is of crucial importance for reducing the cost and enhancing the catalytic activity. In this work, the reactivity of Cu-Au alloy monolayer supported on WC for HER is investigated using density functional theory (DFT) calculations, and the results are compared with those of the supported pure monolayer ones. It is found that the Cu-Au alloy monolayers on WC exhibit enhanced stability and tunable HER activity. Superior activity of Cu2Au7d@WC(0001) for HER (Delta G = 0.007 eV) is identified according to the calculated Gibbs free energy and the exchange current density. Geometric and electronic analyses enable to a deep understanding on the important role of the specific configuration and ratio of Cu and Au for moderate H adsorption. Cu doping leads to the synergistic ligand and stress effects in the alloy systems, which further optimize the adsorption characters and the charge redistribution around the dopants, which is essential to the high HER activity. The present study sheds light on the significance of alloy effects on tuning the geometric stability and electronic properties as well as the catalytic activity, which may benefit to the rational design and development of supported alloy materials.