Unlocking low-temperature and anti-SO2 poisoning performance of bimetallic PdV/TiO2 catalyst for chlorobenzene/NOx catalytic removal by antimony modification design

Abstract

Controlling chlorobenzene (CB) and NOx emissions via catalytic oxidation and selective catalytic reduction necessitates high redox performance catalysts, and construction of active centers with multiple adsorption centers towards reactants is prerequisite for developing such catalysts. Herein, the electronic structure and active centers of the PdV/TiO2 bimetallic catalyst were modulated by Sb modification. The neighboring antimony (Sb) promoted the charge transfer between V and Pd centers, and suppressed the adsorption of SO2 on active sites, thus accelerating CB/NOx conversion and significantly avoiding the deposition of sulfur species on the active centers, especially the Pd species. The detailed plausible CB/NOx catalytic removal pathway (CBfree → CBads → C6H5ads + Clads + O species (Olatt and Oads) → CxHyOz + Clads + Brønsted → CO2 + H2O + HCl on SbPdV/TiO2 catalyst surface was further established. This research provided a strategy for the development of improved CB catalytic oxidation + selective catalytic reduction (CBCO + SCR) catalysts by tuning the electronic structure of active centers.