TiO2 surfaces self-doped with Ag nanoparticles exhibit efficient CO2 photoreduction under visible light.

ABSTRACT

Doping with intrinsic defects to enhance the photocatalytic performance of TiO2 has recently attracted attention from many researchers. In this report, we developed an original approach to realise stabilized surface doping using intrinsic defects with the loading of Ag nanoparticles (AgNPs) on the surface. Herein, atmospheric pressure dielectric barrier discharge (DBD) cold plasma was used to help load the AgNPs, and ethanol treatment was used to introduce intrinsic defects (oxygen vacancies and Ti3+) on the surface of materials. This method avoids environmentally hazardous reducing regents and is undertaken under atmospheric pressure, thus reducing energy-consuming and complex operation. We combine the advantages of noble metal nanoparticles and surface doping to enhance the photocatalytic performance under the visible light. The characterization of the materials indicates that the loading of AgNPs and introduction of intrinsic defects can change the electronic structure of the composite material and improve its efficiency. The samples show significant enhancement in CO2 photoreduction to obtain CO and CH4, with yields reaching 141 µmol m-2 and 11.7 µmol m-2, respectively. The formation mechanism of the method for TiO2 modification and CO2 reduction is also discussed.