Interfacial Active-Oxygen Transport in Inverse CuO_x/Perovskite Catalysts for Low-Temperature CO Oxidation

Developing earth-abundant catalysts for low-temperature carbon monoxide (CO) oxidation is important for next-generation emission control, particularly in industrial scenarios where precious-metal catalysts face cost and stability constraints. Here, we report an "inverse" catalyst architecture in which LaMn_0.6Cu_0.4O₃ (LMCO) perovskite is integrated with CuO_x-derived phases to form 80Cu-LMCO. The catalyst reaches a T₉₀ of 60 °C for CO oxidation, outperforming conventional perovskite and copper oxide catalysts under comparable conditions. Unlike previously reported CuO_x or perovskite catalysts, this system uses an inverse CuO_x/perovskite architecture to spatially separate O₂ activation from CO adsorption while coupling these processes through interfacial active-oxygen transport. In situ spectroscopy, ¹⁸O₂ isotopic-exchange experiments, and density functional theory (DFT) calculations further support this pathway by showing that LMCO activates oxygen and provides labile oxygen species, whereas reduced Cu-containing phases provide CO adsorption sites and mediate oxygen transfer toward interfacial Cu⁺ species. This active-oxygen transport pathway provides a mechanistic basis for designing robust, low-cost catalysts for low-temperature oxidation reactions.