Superior photocatalytic disinfection effect of Ag-3D ordered mesoporous CeO2 under visible light

Ordered mesoporous Ag/CeO2 nanocomposites were prepared by combining nanocasting with photo-assisted reduction. The heterogeneous photoreactivity of the prepared samples was tested for inactivating Escherichia coil (E. coll.). These mesoporous Ag/CeO2 nanocomposites exhibited superior photocatalytic disinfection efficiency than mesoporous CeO2 and bulk CeO2, respectively. Doping Ag species could extend the absorption range to visible light area and enhance the concentration of Ce3+ ions and oxygen vacancies, which had significant influence on the surface properties of CeO2. Moreover, it is the first time to verify that created midgap states through doping Ag can significantly lower the threshold of incident photon energy and broaden the adsorption spectrum demonstrated by experimental studies and density functional theory (DFT) calculations. The enhanced disinfection mechanism was attributed to the fact that the novel mesoporous structure can promote the mass transfer process and the interfacial interaction between Ag species and CeO2 and lead to reduced recombination of free charges, rapid separation and transportation of photogenerated electrons-holes. This work provides a new method to develop novel mesoporous plasmonic photocatlysts for disinfection using solar radiation.