CO2 hydrogenation on CeO2@Cu catalyst synthesized via a solution auto-combustion method

Cu-based catalysts had been widely used in CO 2 hydrogenation process for their excellent performance and high selectivity. Micron-sized Cu powder obtained by ball milling exhibited poor CO 2 activity for its large particle size and small specific surface area, limited its catalytic application. In this work, micron Cu powder was modified with CeO 2 species synthesized from different cerium precursor salts via a solution auto-combustion method to investigate CO 2 hydrogenation activity. This work revealed that CeO 2 species formed from cerium acetate precursor salt achieved excellent CO 2 performance (1.64 mol/g cat .h at 400 °C), which was 3.8 times and 6000 times higher than that from cerium nitrate salt or cerium chloride salt, respectively. Interestingly, a thick dense CeO 2 shell would be formed on micron Cu generated from cerium(III) chloride precursor salt, which inhibited CuO x reduction and had the opposite effect for RWGS reaction. In addition, the CuO x species in CeO 2 @Cu synthesized from cerium chloride salt resulted in the CH 4 selectivity. The enhancement performance of the CeO 2 @Cu prepared from cerium acetate salt and cerium nitrate salt could be attributed to the oxygen defects formed around the Cu-Ox-Ce interface area and metallic Cu in the RWGS reaction. Cerium precursor salts enhanced the structural integrity of CeO 2 @Cu and played a vital role in RWGS reaction. These results will support a new direction for exploring micron Cu powder in Cu-based catalysts for CO 2 utilization.