The p–n heterojunction with porous BiVO4 framework and well-distributed Co3O4 as a super visible-light-driven photocatalyst

Abstract

The p–n heterojunction with mesoporous BiVO₄ framework well-distributed Co₃O₄ is fabricated. The mesoporous structure is prepared by nanocasting technique using KIT-6 as template, while the incorporation of Co₃O₄ particles is completed by the impregnation technique. Transmission electron microscopy (TEM) image shows that Co₃O₄ particles have been successfully loaded in the framework of the mesoporous BiVO₄. Energy dispersive spectrum (EDS) mapping reveals that Co₃O₄ particles distribute uniformly in the sample, which is the result of the template effect of the mesoporous structure. The photocatalytic removal rate of RhB with BiVO₄ is enhanced by the construction of the p–n heterojunction of Co₃O₄/mesoporous BiVO₄. This increase can be attributed to the enhanced separation efficiency of the photogenerated charge carriers produced by the p–n heterojunction. Mesoporous BiVO₄ enables the guest material of Co₃O₄ to be well distributed in the matrix of the mesoporous BiVO₄, thereby providing a large contact area of Co₃O₄ and BiVO₄. This promotes the charge transferring across the interface, thereby increasing the separation of electron–hole pairs, and leading to the enhancement of photocatalytic ability. Furthermore, the mesoporous structure itself contributes to the enhanced photocatalytic performance.