Synthesis of plasmonic enhance sphere-like Ag/AgI/Bi₅O₇I photocatalysts with improved visible-light responsive activity under LED light irradiation

Coupling surface plasmon with semiconductor has been demonstrated to be an efficient strategy for improving the photocatalytic performance of the photocatalyst. The sphere-like Ag/AgI/Bi₅O₇I composites were synthesized by a hydrothermal-decomposition process, followed by an in-situ ion exchange reaction. Under LED lamp irradiation (400 < λ < 800 nm), the as-prepared Ag/AgI/Bi₅O₇I displayed a great enhancement in photocatalytic activities for the degradation of organic dyes (Rhodamine B and methyl orange), as compared with the pure orthorhombic phase Bi₅O₇I. The scavenger test results indicated that the photo-generated h⁺ would play an important role in the degradation of organic pollutants. Moreover, the Ag/AgI/Bi₅O₇I nanocomposite generates high photoactivity in the cycling photocatalytic test. According to the experimental results, the possible photocatalytic degradation mechanism of Ag/AgI/Bi₅O₇I was also proposed. From our perspective, this advantage is mainly ascribed to two aspects: (i) the surface plasmon resonance effect of Ag nanoparticles; (ii) the highly efficient separation of electrons and holes through the closely contacted interfaces in the Ag/AgI/Bi₅O₇I system.