Unravelling the real active center for CO oxidation-Cu+ or Cu3+: A case of model LaCuO3/MCF

Cu-based catalysts are one of the promising alternatives for industrial carbon monoxide (CO) oxidation appli-cations. However, the exact active sites as well as their natures for CO oxidation have been still not fully un-derstood yet. Herein, we designed and constructed a nano-size LaCuO3 perovskite oxide supported on inactive mesocellular siliceous foam (MCF), in which, the Cu species is featured by Cu3+. Then, LaCuO3-y/MCF with abundant Cu+ species was obtained by treating the as-prepared LaCuO3/MCF in H2/N2 flow. The catalytic ac-tivities of LaCuO3/MCF and LaCuO3-y/MCF were investigated for CO oxidation. The experimental results revealed that the Cu+ species rather than Cu3+ was the reactive site for CO oxidation. Moreover, density func-tional theory (DFT) calculations uncovered that the Cu+ species not only considerably facilitated the adsorption of CO and O2, but also dramatically reduced the desorption energy of CO2 from defective surface, thereby enhancing the catalytic activity of CO oxidation over Cu+ notably.

Automated summary

This study investigates the active sites and their properties in CO oxidation of Cu-based catalysts. The experimental results demonstrate that Cu+ species are the main active sites for CO oxidation. DFT calculations reveal that Cu+ species greatly facilitate the adsorption of CO and O2, and reduce the desorption energy of CO2, thereby significantly enhancing the catalytic activity of CO oxidation.