Multi-functional Ag/Ag3PO4/AgPMo with S-scheme heterojunction for boosted photocatalytic performance

Environmental issues caused by various pollutants has aroused wide concern. Designing S-scheme heterojunction photocatalysts has been a promising approach. Strengthening its efficient charge transport routes with the assist of noble metal nanoparticles is potential to achieve high-efficiency wastewater treatment. An improved S-scheme heterojunction Ag/Ag3PO4/Ag3PMo12O40 (Ag/Ag3PO4/AgPMo) was fabricated via the hydrothermal method and in-situ UV reduction process. The loading of Ag0 led to multiple effects: a broad spectral response and a sufficient charge transfer via surface plasmon resonance (SPR) and the Schottky effect. The as-prepared Ag/Ag3PO4/AgPMo composite can completely reduce Cr(VI) within 90 min under visible light, and the rate constant attained 0.029 min−1, which was 29.0 times that by pure AgPMo. Moreover, the composite also displayed excellent tetracycline hydrochloride (TC) removal efficiency, and the value was 97% within 180 min. Interestingly, efficient treatment can also be applied to mixed wastewater containing organic matters (i. e. phenol, dyes, EDTA-2Na) and Cr(VI). The boosted performance can be ascribed to a stepwise path of charge transfer, which is an improved S-scheme heterojunction assisted by multi-effect Ag nanoparticles. Overall, this study opens a new strategy for the preparation of polyoxometalate-based composite for the photocatalytic disposal of hazardous pollutants.