Macroporous V₂O₅−BiVO₄ Composites: Effect of Heterojunction on the Behavior of Photogenerated Charges

Abstract

Macroporous V2O5−BiVO4 composites with a heterojunction structure have been successfully synthesized under the assistance of colloidal carbon spheres. X-ray diffraction, Raman, and X-ray photoelectron spectroscopies reveal that the as-prepared composites are composed of monoclinic BiVO4 and orthorhombic V2O5. The behavior of photogenerated charges in V2O5, BiVO4, and the V2O5−BiVO4 composite have been investigated through surface photovoltage spectroscopy (SPS) and transient photovoltage (TPV) techniques. It is demonstrated that the formation of heterojunction structure in the V2O5−BiVO4 composite plays an important role in the kinetic behaviors (including separation, transport, and recombination) of photogenerated charges. The heterojunction greatly increases the separation extent and the lifetime of the photogenerated charges in the composites.