Mesoporous Cu‐Ce‐Ox Solid Solutions from Spray Pyrolysis for Superior Low‐Temperature CO Oxidation

Development of Pt group metal‐free catalysts for low‐temperature CO oxidation remains critical. In this work, active and stable mesoporous Cu‐Ce‐Ox solid solutions are prepared by using spray pyrolysis. The specific surface areas and pore volumes reach as high as 170 m2 g−1 and 0.24 cm3 g−1, respectively. The results of CO oxidation study suggest that (1) the catalyst obtained by spray pyrolysis possesses much higher activity than those made by co‐precipitation, sol‐gel, and hydrothermal methods; (2) the optimal Cu0.2‐Ce0.8‐Ox solid solution presents a reactivity over 28 times that of both single‐component CuO and CeO2 at 70 °C. Based on the study of pure‐phase Cu‐Ce‐Ox solid solutions by selective leaching of segregated CuOx species, the active center for CO oxidation is confirmed as the bimetallic Cu‐Ce‐O site, whereas the individual CuOx particles not only act as spectators but also block the active Cu‐Ce‐O sites. A low apparent activation energy of approximately 48 kJ mol−1 is detected for CO oxidation at the Cu‐Ce‐O site, making Cu‐Ce‐Ox solid solutions able to present high activity at low temperature. Furthermore, the Cu‐Ce‐Ox catalysts exhibit excellent stability and thermal tolerance toward CO oxidation. Pt‐free CO oxidation: Well‐shaped mesoporous Cu‐Ce‐Ox solid solutions were produced for low‐temperature CO oxidation by using a nitrate spray pyrolysis route, and a selective leaching strategy was adopted to remove the surface segregated CuOx species. The bimetallic Cu‐Ce‐O site was confirmed as the active center for CO oxidation, whereas the individually segregated CuOx species not only acted as spectators, but also blocked the active Cu‐Ce‐O sites (see scheme).