Abstract
•BiVO4/Ag3PO4/PANI combined with facet engineering and heterojunction was prepared.•Built-in electric field and hole transfer promoted the charge carriers separation.•Optimal photocatalytic activity and stability for CIP degradation was obtained.•The mechanism of enhanced photocatalytic performance was proposed.
Considering that the crystal facet is highly correlated with the photocatalytic performance of the semiconductor, a novel BiVO4/Ag3PO4/PANI photocatalyst combined with facet engineering and heterojunction is prepared by depositing Ag3PO4 on the highly active (0 4 0) facet of BiVO4 and then incorporating polymer polyaniline (PANI). The synergistic modification of Ag3PO4 and PANI realizes excellent photocatalytic performance, with the degradation efficiency of 85.92% and the maximum rate constant of 0.00894 L mg−1 min−1, which is 10.1, 5.6 and 1.6 times than that of BiVO4, BiVO4/PANI and BiVO4/Ag3PO4, respectively. This enhanced photocatalytic performance is attributed to the following: (i) selective exposure of highly active BiVO4 (0 4 0) facet greatly improves the spatial separation efficiency of charge carriers; (ii) the (0 4 0) facet with preferentially exposed low-coordinated oxygen atoms provides sufficient binding sites for Ag+ anchoring, resulting in strong interfacial coupling between BiVO4 and Ag3PO4, which facilitates charge separation and transfer; (iii) the CB-electrons of Ag3PO4 can be timely consumed by the VB-holes of BiVO4 by the built-in electric field, thus preventing photo-corrosion of Ag3PO4; (iv) PANI acting as hole-transfer material can rapidly migrate holes accumulated in the VB of Ag3PO4 to the catalyst surface by its HOMO orbital, thereby achieving efficient charge separation; (v) the introduction of PANI results in a significant increase in visible light absorption efficiency. This work provides a novel design based on facet engineering and heterojunction, which can also be employed to other semiconductors to improve photocatalytic performance.