Uniform spatial distribution of a nanostructured Ag/AgCl plasmonic photocatalyst and its segregative membrane towards visible light-driven photodegradation

Abstract

A uniform spatially distributed Ag/AgCl nanostructure on a hierarchical titanate microsphere (TMS) was rationally designed for visible light-driven water purification. The hierarchical TMS was firstly prepared by a one-step hydrothermal method, and then the AgCl nanoparticles were grown on the surface of TMS via a unique ion-exchange method. Eventually, anti-aggregated Ag/AgCl/TiO₂ microsphere hybrid photocatalysts were obtained after heat treatment and light irradiation. The Ag/AgCl/TiO₂ microsphere treated at 400 °C exhibits the best photocatalytic activity, which is six times better than that of pure Ag/AgCl. This is attributed to the uniform spatial distribution of Ag/AgCl nanoparticles, better light absorption efficiency within the hierarchical microsphere, and better separation of photo-generated charges with the synergistic effect of TiO₂ microspheres and Ag/AgCl. More impressively, a free-standing and segregative membrane made of Ag/AgCl/TiO₂ microspheres also shows excellent photocatalytic performance in degrading methyl orange (MO) and methylene blue (MB) dyes under visible range radiation. Our results validate that the as-prepared Ag/AgCl/TiO₂ microsphere plasmonic photocatalyst provides an efficient way to realize organic pollutant removal under visible light.