Catalytic Oxidation of Chlorobenzene over HSiW/CeO as a Co-Benefit of NO Reduction: Remarkable Inhibition of Chlorobenzene Oxidation by NH.

There is an urgent need to develop novel and high-performance catalysts for chlorinated volatile organic compound oxidation as a co-benefit of NO. In this work, HSiW/CeO was used for chlorobenzene (CB) oxidation as a co-benefit of NO reduction and the inhibition mechanism of NH was explored. CB oxidation over HSiW/CeO primarily followed the Mars-van-Krevelen mechanism and the Eley-Rideal mechanism, and the CB oxidation rate was influenced by the concentrations of surface adsorbed CB, Ce ions, lattice oxygen species, gaseous CB, and surface adsorbed oxygen species. NH not only strongly inhibited CB adsorption onto HSiW/CeO, but also noticeably decreased the amount of lattice oxygen species; hence, NH had a detrimental effect on the Mars-van-Krevelen mechanism. Meanwhile, NH caused a decrease in the amount of oxygen species adsorbed on HSiW/CeO, which hindered the Eley-Rideal mechanism of CB oxidation. Hence, NH significantly hindered CB oxidation over HSiW/CeO. This suggests that the removal of NO and CB over this catalyst operated more like a two-stage process rather than a synergistic one. Therefore, to achieve simultaneous NO and CB removal, it would be more meaningful to focus on improving the performances of HSiW/CeO for NO reduction and CB oxidation separately.