Visible-light-active plasmonic Ag–SrTiO₃ nanocomposites for the degradation of NO in air with high selectivity

Harnessing inexhaustible solar energy for photocatalytic disposal of nitrogen oxides is of great significance nowadays. In this study, Ag–SrTiO₃ nanocomposites (Ag–STO) were synthesized via one-pot solvothermal method for the first time. The deposition of Ag nanoparticles incurs a broad plasmonic resonance absorption in the visible light range, resulting in enhanced visible light driven activity on NO removal in comparison with pristine SrTiO₃. The Ag loading amount has a significant influence on light absorption properties of Ag–STO, which further affects the photocatalytic efficiency. It was shown that 0.5% Ag loading onto SrTiO₃ (in mass ratio) could remove 30% of NO in a single reaction path under visible light irradiation, which is twice higher than that achieved on pristine SrTiO₃. Most importantly, the generation of harmful intermediate (NO₂) is largely inhibited over SrTiO₃ and Ag–STO nanocomposites, which can be ascribed to the basic surface property of strontium sites. As identified by electron spin resonance (ESR) spectra,·O₂– and ·OH radicals are the major reactive species for NO oxidation. Essentially speaking, the abundance of reactive oxygen radicals produced over Ag–STO nanocomposites are responsible for the improved photocatalytic activity. This work provides a facile and controllable route to fabricate plasmonic Ag–SrTiO₃ nanocomposite photocatalyst featuring high visible light activity and selectivity for NO abatement. Copyright © 2016 American Chemical Society.