A novel efficient visible-light-driven double Z-scheme PANI/Ag3PO4/CNO heterojunction photocatalyst mediated by PANI and in situ grown AgNPs

Degrading organic pollutants from semiconductor photocatalysis technology is an attractive alternative to other advanced oxidation technologies, thanks to its green energy characteristics, mild reaction conditions, freedom from secondary pollution and ability to produce rich free radical species. Herein, we demonstrate the efficient degradation of several organic dyes and their mixture, which is achieved over a double Z-scheme PANI/Ag3PO4/g-C3N4-O (CNO) heterojunction catalyst and driven by visible light. With this degradation, the apparent degradation rate for RhB was up to 0.2668 min−1, which was approximately 1.31, 2.68, 5.28 and 17.12 times faster than those of PANI/Ag3PO4, Ag3PO4/CNO, Ag3PO4 and CNO, respectively. It also exhibited excellent activity for mixed dyes. Furthermore, the double Z-scheme heterojunction photocatalytic system built around Ag3PO4, which was presented and confirmed by researching the band structures of the three semiconductors and conducting radical scavenging experiments, greatly accelerates the transfer of photogenerated electrons on the conduction band of Ag3PO4; thereinto, both PANI and in situ grown AgNPs act as electron mediators, thereby improving the activity and stability of Ag3PO4. This work puts forward a novel perspective for heightening the activity and stability of perishable photocatalysts for organic dye effluent and other organic pollutant treatments.