Voltage-dependent reconstruction of layered Bi2WO6 and Bi2MoO6 photocatalysts and its influence on charge separation for water splitting

We study the surface stability of the layered bismuth-oxide Bi2WO6 and Bi2MoO6 photocatalysts, which belong to the series of Aurivillius (Bi2An-1BnO3n+3) perovskites and have been proposed as efficient visible-light absorbers, due to favorable electronic hybridization induced by the bismuth 6s and 6p orbitals. We present a Newton-Raphson optimization of the charge distribution at the semiconductor-solution interface using the self-consistent continuum solvation (SCCS) model to describe the influence of the aqueous environment. Our analysis provides a description of the charged interface under controlled pH and applied voltage and offers a molecular interpretation of the competing structural and electrical factors that underlie the facet-dependent photocatalytic activity of layered Bi2An-1BnO3n+3 compounds.