The Dual Function of Lattice Oxygen Activation and Adsorption Site Regulation by Cu in CeTiO ₂ Catalysts: Advancing Simultaneous Catalytic Removal of NO <i> _x </i> and CO

The challenge of tackling atmospheric pollutants and the demand for low-carbon environmental technologies have imposed urgent requirements on the control of CO and NOx pollutants. Synergistic catalytic treatment is regarded as the most ideal emission reduction technique, with the difficulty lying in simultaneously enhancing catalytic activity and resolving competitive adsorption. In this work, the Cu component was incorporated into the CeTiO2 catalyst. The optimized Cu2/CeTiO2 catalyst achieved over 90% conversion for both CO and NOx across a broad temperature range of 225–325 °C. Characterization and theoretical calculations demonstrated that Cu doping decreased the valence state of Ce and Ti sites, thereby enhancing lattice oxygen activation and migration ability. The increased CO adsorption also contributed to the elevated CO oxidation activity. The broadening of the simultaneous removal temperature range was achieved by eliminating competitive adsorption of reactants. Specifically, the competitive adsorption between NH3 and CO was mitigated after Cu doping. NO was primarily adsorbed at the Ce and Ti sites, while Cu was engineered as the CO capture site. This substantially reduced the competitive adsorption between the two reaction atmospheres, enabling simultaneous removal of both pollutants. This research offers a reliable approach and catalyst construction strategy for the simultaneous removal of CO and NOx, thereby advancing the development of pollution reduction and carbon mitigation technologies.