Nanostructured BiVO4 obtained by the vanadium calcination of Bi2O3 nanohelixes for enhanced photoelectrochemical water splitting

Abstract

Although BiVO₄ has been investigated as a promising photoanode for solar water splitting, the lack of a nanostructure synthesis method that provides the controllability of the stoichiometric composition prevents the realization of a high-performance BiVO₄ photoanode. This paper presents an effective and simple synthetic method for fabricating BiVO₄ with a high-quality and unique nanostructure from an array of Bi₂O₃ nanohelixes using oblique angle deposition via vanadium calcination. The porous open structure of the nanohelical Bi₂O₃ array facilitates the intrusion of vanadium solution during the solvothermal process, thus allowing for the formation of a BiVO₄ nanostructural array with high crystallinity. The combination of significant light-scattering, improved charge separation, and an enlarged active surface area allows for the unique BiVO₄ nanostructure to exhibit enhanced optical properties and a photocurrent density of 2.6 mA cm⁻² at 1.23 V versus the reversible hydrogen electrode.