Mesoporous Cu‐Ce‐O x 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‐O x solid solutions are prepared by using spray pyrolysis. The specific surface areas and pore volumes reach as high as 170 m 2  g −1 and 0.24 cm 3  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 Cu 0.2 ‐Ce 0.8 ‐O x solid solution presents a reactivity over 28 times that of both single‐component CuO and CeO 2 at 70 °C. Based on the study of pure‐phase Cu‐Ce‐O x solid solutions by selective leaching of segregated CuO x species, the active center for CO oxidation is confirmed as the bimetallic Cu‐Ce‐O site, whereas the individual CuO x 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‐O x solid solutions able to present high activity at low temperature. Furthermore, the Cu‐Ce‐O x catalysts exhibit excellent stability and thermal tolerance toward CO oxidation.