Boosting synergistic catalytic abatement of NO_x and chlorobenzene via bidirectional promotion of Nb within asymmetrical Ce-O-Nb sites

The synergistic catalytic abatement of nitrogen oxides (NO_x) and chlorinated aromatic pollutants remains a significant challenge. The matching of the active temperature window and the trade-off between catalytic activity and selectivity are two principal issues to be concerned with. In this context, adding niobium oxide into the titania-supported cerium oxide (CeNbTi) catalyst markedly enhanced the synergistic catalytic activity and stability. The asymmetrical Ce-O-Nb structure was verified to be constructed on the CeNbTi catalyst. Nb demonstrated a dual modulation of redox and acidity, enabling a balance of dual sites for two cycles. This led to a simultaneous improvement in NH₃-SCR and chlorobenzene oxidation performance. In situ DRIFTS indicated a synergistic promotion mechanism that chlorobenzene oxidation utilizes highly reactive oxidizing species, reducing NH₃ excessive oxidation and lowering N₂O production from the NH₃-SCR pathway. This study offers a strategy via designing asymmetrical sites to develop catalysts for controlling multiple pollutants.