Theoretical insights into the mechanism of oxygen evolution reaction (OER) on pristine BiVO₄ (001) and BiVO₄ (110) surfaces in acidic medium both in the gas and solution (water) phases

Monoclinic scheelite bismuth vanadate is an efficient photocatalyst for water splitting. In this paper, we perform DFT + U calculations to investigate the structural, electronic, and optical properties, water adsorption and the oxygen evolution reaction processes on BiVO₄ (001) and BiVO₄ (110) surfaces in acidic medium both in the gas and solution (water) phases. The structural, electronic, optical, and water adsorption properties reveal that BiVO₄ (001) surface is energetically more stable than BiVO₄ (110) surface in vacuum. On other hand, the water oxidation mechanisms reveal that BiVO₄ (110) surface in water and in strained form in vacuum is energetically more stable than BiVO₄ (001) surface in water and in strained form in vacuum both U = 0 and 2.1 V. The free energy of adsorption for all systems at U = 2.1 V reduce about 2 times than that at U = 0 V. Such analyzes provide important insights into the role of different facets on BiVO₄ surface for photocatalytic reactions. (paper)