Construction of Cu-Fe bimetallic oxide/biochar/Ag3PO4 heterojunction for improving photocorrosion resistance and photocatalytic performance achieves efficient removal of phenol

Abstract

Ag3PO4 has an excellent visible light response, but its serious photocorrosion has limited its application in environmental remediation. Here, we constructed a ternary heterojunction photocatalyst (CuFe2O4/Biochar/Ag3PO4) to inhibit its photocorrosion and enhance photocatalytic activity. Notably, the composite catalyst (0.5 g/L) thoroughly degraded phenol (20 mg/L) at 18 min, and its apparent kinetic constant is fivefold that of pure Ag3PO4. The analysis of XPS, XRD, and cyclic degradation experiments confirmed that the photocorrosion of the heterojunction photocatalyst was significantly suppressed. The enhanced photocorrosion resistance of Ag3PO4 can be ascribed to the rapid transfer and consumption of photoelectrons on the Ag3PO4 surface by biochar and CuFe2O4, thereby avoiding photocorrosion. Especially, Ag3PO4 as a hole-rich region can protect Ag+ from being reduced. DFT calculations further revealed the electron transfer and anti-photocorrosion mechanism of Ag3PO4. The photogenerated O2– and h+ played a major role in phenol degradation. A possible degradation pathway was proposed by DFT calculations and GC–MS analysis. This study provides a novel ternary heterojunction photocatalyst to improve the catalytic performance and photocorrosion resistance of Ag3PO4.