Phosphate-Functionalized CeO2 Nanosheets for Efficient Catalytic Oxidation of Dichloromethane

Tuning the nature and profile of acidic and basic sites on the surface of redox-active metal oxide nanostructures is a promising approach to constructing efficient catalysts for the oxidative removal of chlorinated volatile organic compounds (CVOCs). Herein, using dichloromethane (DCM) oxidation as a model reaction, we report that phosphate (PO x ) Brønsted acid sites can be incorporated onto a CeO 2 nanosheet (NS) surface via an organophosphate-mediated route, which can effectively enhance the CeO 2 ’s catalytic performance by promoting the removal of chlorine poisoning species. From the systematic study of the correlation between PO x composition, surface structure (acid and basic sites), and catalytic properties, we find that the incorporated Brønsted acid sites can also function to decrease the amount of medium-strong basic sites (O 2– ), reducing the formation of chlorinated organic byproduct monochloromethane (MCM) and leading to the desirable product, HCl. At the optimized P/Ce ratio (0.2), the PO x –CeO 2 NSs can perform a stable DCM conversion of 65–70% for over 10 h at 250 °C and over 95% conversion at 300 °C, superior to both pristine and other phosphate-modified CeO 2 NSs. Our work clearly identifies the critical role of acid and basic sites over functionalized CeO 2 for efficient catalytic CVOCs oxidation, guiding future advanced catalyst design for environmental remediation.