Accelerating carrier separation of Ag3PO4 via synergetic effect of PANI and rGO for enhanced photocatalytic performance towards ciprofloxacin

To solve severe photocorrosion of Ag3PO4, polyaniline for transporting holes and reduced graphene oxide (rGO) for transferring electrons were co-incorporated with Ag3PO4 by an in-situ precipitation procedure and a following hydrothermal method, reaching the superior carrier separation efficiency via synergetic effect of PANI and rGO. Consequently, 5% rGO/Ag3PO4/PANI exhibited the excellent photocatalytic performance of 86.2% removal rate towards ciprofloxacin (CIP) within 15 min, which was much better than Ag3PO4, Ag3PO4/PANI and many reported photocatalysts. After four consecutive cycles, the composites performed better stability with 81.0% removal rate. Generally, photocatalytic activity depended on efficiencies of light absorption (ηabs), charge separation (ηsep) and charge injection (ηinj). ηsep of rGO/Ag3PO4/PANI was 11.5 and 8.70 folds higher than that of Ag3PO4 and Ag3PO4/PANI, while ηabs and ηinj of rGO/Ag3PO4/PANI were not improved compared with Ag3PO4 and Ag3PO4/PANI, strongly manifesting synergetic effect of PANI and rGO on Ag3PO4 accelerated the charge separation and finally enhanced the photocatalytic activity. Besides, rGO greatly improved the adsorption efficiency for CIP and the maximum adsorption capacity was enhanced to be 19.4 mg/g which was 6.88 folds than that of Ag3PO4, being advantageous to enhancing the photocatalytic activity. The work offered an excellent reference for designing and constructing photocatalysts with superior charge separation showing excellent photocatalytic performance, which were potential candidates for degrading antibiotics in environmental treatment.