First-principles study of catalytic activity of W-doped cobalt phosphide toward the hydrogen evolution reaction

In this study, we investigated the hydrogen evolution reaction (HER) on the (101) facet of pristine and W-doped CoP using the density functional theory. Two types of Co atoms are identified on the catalyst surface: the Co atoms that present the higher d band center are marked as valid sites, whereas the others are marked as invalid sites owing to their weaker H adsorption ability. It is further revealed that W-doping can decrease the d band center of the surface Co atoms, which is beneficial for the HER; however the exposure to W weakens the desorption of H. To address the strong adsorption effect of W, the doping sites and dopant content are analyzed, and the results indicate that 8.4 wt% W doping at the invalid surface Co sites is preferred; moreover, the optimal W content increases to 16.8 wt% when W is inserted into the subsurface. The effect of W doping is weakened when the doping site is far away from the surface. (c) 2020, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.