Photothermocatalytic synergistic oxidation: An effective way to overcome the negative water effect on supported noble metal catalysts for VOCs oxidation

Abstract

Thermocatalytic oxidation over supported noble metal catalysts shows a promising application prospect in eliminating VOCs. However, the high consumption of the expensive noble metals and input energy as well as catalyst deactivation from H2O poisoning limit its practical application. Herein, we report that photothermocatalytic synergistic oxidation over bifunctional supported noble metal catalysts can attenuate the negative effect of H2O vapour and achieve efficient mineralization of aromatic VOCs with high concentration at a low Pt loading and a mild temperature. Photothermocatalytic synergistic oxidation of aromatic VOCs was performed over bifunctional Pt/SrTiO3-x with a low 0.1 wt% Pt loading in the co-presence of visible-light illumination and mild thermal energy input (≤150 °C), achieving much more effective mineralization of toluene in high concentrations than the pristine thermocatalytic or photocatalytic oxidation. The introduction of photocatalysis lowers the activation energy and attenuates the negative H2O effect in the conventional thermocatalytic process through activating oxygen and consuming H2O for oxidative species O2− and OH production with photogenerated charges. Such a finding may provide some new insight into the construction of robust photothermocatalytic process and catalysts for efficient and economic VOCs elimination.