Improved ionic organic pollutant degradation under visible light by Ag SPR-promoted phosphorus-doped g-C3N4/AgBr/Bi2WO6 with excellent charge transfer capacity and high surface area

Abstract

Graphite carbon nitride (g-C3N4) has a strong photocatalytic capability to degrade ionic organic compounds due to its unique electrical structure with numerous marginal amino groups. A photocatalyst was fabricated via a facile in-situ sedimentation–calcine–hydrothermal method by anchoring AgBr and Bi2WO6 onto the framework of phosphorus-doped g-C3N4 (PCAB). The photocatalyst has been proven to have good photocatalytic degradation effect on different ionic organic pollutants. The removal rate of tetracycline, the target pollutant, can reach 99.2%, which was 1.83 times higher than that of g-C3N4 within 60 min under visible light. Moreover, the degradation rates of dyes containing azo bonds and -SO3H can reach 100% within 20 min, as determined by the electrical relationship between the catalyst and the dye. The excellent performance can be attributed to the synergistic effect of the formation of mid-gap in g-C3N4 after phosphorus doping, improvements in charge carrier transfer and the low recombination rate based on the construction of dual Z-scheme heterojunction and Ag bridge. In addition, cycling experiments and characterizations illustrated the high stability and reusability of PCAB. The main active species during photocatalytic process was·O2−, whereas h+ and·OH played a minimal role. Ultimately, a dual Z-scheme mechanism was proposed to explain the photocatalytic reaction.