Synergistic Catalytic Elimination of NOx and Chlorinated Organics: Cooperation of Acid Sites.

Abstract

The synergistic catalytic removal of NOx and chlorinated volatile organic compounds under low temperatures is still a big challenge. Generally, degradation of chlorinated organics demands sufficient redox ability, which leads to low N2 selectivity in the selective catalytic reduction of NOx by NH3 (NH3-SCR). Herein, mediating acid sites via introducing the CePO4 component into MnO2/TiO2 NH3-SCR catalysts was found to be an effective approach for promoting chlorobenzene degradation. The observation of in situ diffuse reflectance infrared Fourier transform (in situ DRIFT) and Raman spectra reflected that the Lewis acid sites over CePO4 promoted the nucleophilic substitution process of chlorobenzene over MnO2 by weakening the bond between Cl and benzene ring. Meanwhile, MnO2 provided adequate Brønsted acid sites and redox sites. Under the cooperation of Lewis and Brønsted acid sites, relying on the rational redox ability, chlorobenzene degradation was promoted with synergistically improved NH3-SCR activity and selectivity. This work offers a distinct pathway for promoting the combination of chlorobenzene catalytic oxidation and NH3-SCR, and is expected to provide a novel strategy for synergistic catalytic elimination of NOx and chlorinated volatile organic compounds.