Construction and characterization of Ag/AgI/Ag3BiO3 heterojunction and its photocatalytic mechanism

Abstract

In this work, a new ternary Ag/AgI/Ag3BiO3 photocatalyst was fabricated by an in-situ precipitation method, where Ag0 nanoparticles, serving as a mediator, implanted on the surface of glossy AgI, quantum efficiency being improved attributed to the surface plasmon resonance (SPR) effect. The composites showed superior photocatalytic performance to methylene blue (MB) degradation under visible illumination (λ > 420 nm). The Kobs values of Ag/AgI/Ag3BiO3-3 were 7.4 and 3.6 times compared with that of pristine Ag3BiO3 and AgI, respectively. Based on the series of experimental results, a Z-scheme heterojunction has formed in preparations. The electron-hole pairs maintained a transferable cycle, which efficiently inhibited the recombination of electron-hole pairs. According to active species analysis, holes were determined the predominant work-function in photocatalytic degradation system. The feasible mechanism has proposed to illustrate the photocatalytic decomposition of MB on Ag/AgI/Ag3BiO3. Our work has important implication for the management and practical application of catalysts.