Role of surface species in CO oxidation over CuO@LaMnO₃ nanocomposites: Effect of calcination temperature

As one of the main atmospheric pollutants, CO poses great hazards to the living environment. This study synthesized a series of CuO@LaMnO3 nanocomposites via a well-optimized one-step synthesized sol-gel method. All catalysts were calcined at different temperatures (600-800 degrees C) to analyze their impact on the material properties. The appropriate elevation of calcination temperature visibly enhanced the catalytic behavior, due to the greatest activity being gathered on the sample calcinated at 700 degrees C, with nearly 100% conversion for CO at 150 degrees C. Further characterization results revealed that the change in surface species induced by the calcination temperature was a key factor in enhancing catalytic behavior. The coupling of CuO and LaMnO3 induced electron migration and released more Mn4+, Cu+ and O-S, boosting the upgraded adsorption capacity of CO, which served as the inherent motivation for the high activity observed over the CuO@LaMnO3 catalyst. Finally, a possible mechanism model of CO oxidation over the CuO@LaMnO3 catalyst was proposed. Adoption of the innovative composite method herein indeed led to a rich variation in the valence state of the elements on the catalyst surface without the inclusion of copper into the lattice, which in turn caused a significant alteration in the reaction mechanism.