The controllable mutual transformation of Ag+/Ag-0 pairs in Ag3PO4/Bi2MoO6 toward the high catalytic efficiency and durable reusability

摘要

A series of Ag3PO4/Bi2MoO6 p-n heterojunctions were assembled via the thin Bi2MoO6 nanosheets attached to the surface of rhombic dodecahedral Ag3PO4. The self-optimized Ag+/Ag-0 pairs existed in the as-prepared heterojunction which are regarded as charge transmission bridge to accelerate the reaction. The samples presented much higher photocatalytic activity for the degradation of the target pollutions (completely degradation under solar light illuminating of 70min for rhodamine B, 80min for aureomycin and 70min for tetracycline). It was found during the recycle test, photocatalytic performance of Ag3PO4/Bi2MoO6 underwent a successive increase since the second cycle in which the completely degradation of RhB was achieved after only 60min visible light irradiation, confirming the composite is reusable with well stability. The oxidative mechanism was carefully investigation based on the scavengers trapping test, ESR spectra, XPS spectrum, photocurrent responses, and electrochemical impedance spectroscopy analysis. It proved Ag-0 gradually generated from the as-prepared composite under solar light illuminating is fixed at an optimized content. The charge transfer was consequentially enhanced during the suitable level turning of Ag+/Ag-0 pairs. Mediated by Ag-0 sandwiched in p-n junction, the active species of the present photooxidative reaction experienced various period from OH and h(+) in the initial reaction to the additional O-2(-) in the successive recycle experiment owing to generation of the rectifying contact and Schottky junction. This study provides a new cognition for the improved reusability of the photocorrosion materials via the mutual transformation of metal monomers and ions.