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

Abstract

Macroporous V 2 O 5 −BiVO 4 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 BiVO 4 and orthorhombic V 2 O 5 . The behavior of photogenerated charges in V 2 O 5, BiVO 4, and the V 2 O 5 −BiVO 4 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 V 2 O 5 −BiVO 4 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.