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-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. Graphical Pt-free CO oxidation : Well-shaped mesoporous Cu-Ce-O x 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 CuO x species. The bimetallic Cu-Ce-O site was confirmed as the active center for CO oxidation, whereas the individually segregated CuO x species not only acted as spectators, but also blocked the active Cu-Ce-O sites (see scheme).