Engineering stable active Cu0-Cuσ+ sites via in situ surface reconstruction over Cu/CeO2 catalyst for the hydrogenation of carbon-oxygen bonds

Cu/CeO 2 catalysts have been wildly used for the hydrogenation of carbon-oxygen bonds reactions due to their excellent catalytic performance. It is widely accepted that the Cu 0 -Cu σ+ interface could be the primary active sites during the reaction, but how to form and maintain highly dispersed such species remains challenging under the reaction conditions of high temperature and H 2 partial pressure. In this work, we proposed an effective strategy to construct stable Cu 0 -Cu σ+ interface sites over the Cu/CeO 2 catalysts by in situ N 2 O-involved oxidation treatment . It was evidenced that the sequential oxidation-reduction by N 2 O and H 2 broke the grain boundaries of Cu nanoparticles and therefore facilitated the formation of the active Cu 0 -Cu σ+ sites, leading to an enhanced activity. However, a rapid deactivation was observed after this temporary enhancement due to the aggregation of copper species. We further introduced some additional cerium species during catalyst preparation. The 16Cu/CeO 2 -1Ce catalyst prepared by post-impregnation of 1 wt% cerium achieved a stable performance of 90.6% MA conversion after the N 2 O-involved oxidation treatment, which was much higher than that of 26.2% over the 16Cu/CeO 2 catalyst. It was demonstrated that the strong interaction between the formed CeO 2 and reconstructed Cu species prevented the metal sintering and increased the fraction of the Cu 0 -Cu σ+ sites. This method that combined in situ N 2 O-involved oxidation treatment and cerium modification may offer potential in engineering stable active sites for high-performance catalysts in the hydrogenation of carbon-oxygen bonds.