Kinetics investigation of the oxygen evolution reaction on the characteristic facets of γ-Cu3V2O8

Abstract

The sluggish oxygen evolution reaction (OER) kinetics has been confirmed to be the limiting factor for most of photocatalysts. Manipulating the crystal facets of photocatalysts to expose OER active facets is of great significance for increasing the overall efficiency of solar water splitting. McBirneyite (γ-Cu3V2O8) has been characterized as a potential photocatalyst, but there is no experimental or density functional theory (DFT) calculation report on the controlled crystal faces of γ-Cu3V2O8 so far. Therefore, the OER kinetics on the (100), (120), (021), and (002) facets which are the characteristic facets of γ-Cu3V2O8 are studied using the DFT calculations. Our calculations show that the rate-limiting step for OER on these four facets is the dehydrogenation of the *OH species. The dehydrogenation of *OOH is kinetically and thermodynamically favorable on all investigated facets. The V terminals on the surfaces of γ-Cu3V2O8 are found to be superior active sites for the dehydrogenation of H2O. In addition, the product O2 is more easily desorbed from the (100) facets compared to other facets. Our results show that the (100) facet is the most active for OER in all investigated facets of γ-Cu3V2O8.