TiO2 with exposed {001} facets catalyzed peroxone reaction into •O2- and •OH radicals for low temperature NO oxidation

The peroxone reaction (O-3/H2O2) on the surface of TiO2 to generate center dot O-2(-) and center dot OH is an efficient method for pollutant control. In the present work, anatase TiO2 with a high percentage of exposed {001} facets were synthesized and investigated in O-3/H2O2 process, which exhibited an excellent performance for NO oxidation. Experimental results showed that NO oxidation efficiency reached 98 % at the molar ratio of H2O2/NO = 4.36 and O-3/NO = 0.5. The promotion mechanism for NO oxidation was proposed: TiO2 with exposed {001} facets could improve the adsorption of O-3, and enhance the activation of H2O2. A significant synergistic effect between O-3 and H2O2 over TiO2(001) catalyst inducing center dot OH and center dot O-2(-) radicals, which was contributed to NO oxidation. Furthermore, the reaction mechanism of the O-3/H2O2/TiO2(001) process was further revealed by in-situ DRIFTS, and the main product was NO3-. Moreover, O-3/H2O2/TiO2(001) exhibited the stable NO oxidation performance under different gas component including CO, CO2 and SO2.