Exceptional Resistance to Chlorine-Induced Photocatalytic Poisoning via Vacuum UV Irradiation

Catalyst deactivation poses a significant challenge in environmental remediation, especially for the photocatalytic oxidation of chlorinated volatile organic compounds (Cl-VOCs). In this study, a functional flower-like TiO₂@Mn/rGO (FTMG) catalyst coupled with a vacuum ultraviolet (VUV) lamp was used as a novel photocatalytic oxidation (VUV-PCO) system for chlorobenzene (CB) oxidation. In this system, more than 80% of CB was efficiently oxidized at a high w8 hly space velocity of 600,000 g_cat^-1 h^-1, which was a 6.5-fold increase compared to conventional UV-PCO, and no catalytic deactivation over 1300 min of reaction. Notably, the CO_<i>x</i> selectivity consistently reached 100%. These outstanding performances were attributed to the synergy of direct VUV photolysis and gas-solid interface photocatalysis. Importantly, the C-Cl bond of CB was efficiently cleaved by VUV photolysis, generating ^•Cl as the oxidant. Ozone (O₃) generated from VUV photolysis was efficiently adsorbed on oxygen vacancies and Mn (O_v + Mn) adjacent sites on FTMG. These adsorbed O₃ rapidly captured the photogenerated electrons, thereby effectively preventing Cl reduction and avoiding catalyst deactivation. This study sheds light on the unique dechlorination reaction and Cl-poisoning-resistance mechanism in the VUV-PCO system, offering a novel strategy to boost the catalytic oxidation of Cl-VOCs.