One‐step hydrothermal synthesis of the Ag/AgI heterojunction with highly enhanced visible‐light photocatalytic performances

The Ag/AgI heterojunction was prepared by a facile, one‐step and low‐temperature hydrothermal synthesis method with P, I 2 and Ag 2 O. The approach proves a green and simple route to the products, which avoided multiple‐step synthesis and the subsequent time‐consuming photoreduction. The samples were carefully characterised by X‐ray diffraction, X‐ray photoelectronic spectra, scanning electron microscopy, transmission electron micrographs and ultraviolet–visible‐light techniques. The results show that Ag nanoparticles were uniformly distributed on the surface of AgI and the heterostructure was formed. Under visible light, the photocatalytic activity of the Ag/AgI composites for the degradation of rhodamine B (RhB) was efficient and much higher than that of pure AgI. In particular, the Ag/AgI composites (at 120°C for 4 h) exhibited the best photocatalytic activity, and nearly 98% of RhB was degraded within 20 min. Remarkably, the photocatalytic degradation followed the pseudo‐first‐order reaction model and the corresponding apparent first‐order rate constant of 0.157 min −1 which is five times more than that of pure AgI. The enhanced photocatalytic activity of Ag/AgI can be attributed to the strong surface plasmon resonances.