Nanoporous CeO2-Ag catalysts prepared by etching the CeO2/CuO/Ag2O mixed oxides for CO oxidation

Highlights: • Nanoporous CeO₂ catalysts with Ag are successfully achieved by etching the CeO₂/CuO/Ag₂O mixed oxides. • The dissolution of CuO resulted in the construction of ultrafine nanoporous composites. • The specific surface area of the nanoporous CeO₂-Ag catalysts significantly increased. • The nanoporous CeO₂-Ag catalysts exhibited an enhanced catalytic activity and stability toward the oxidation of CO. - Abstract: The uniform nanoporous CeO₂ catalysts with different content of Ag were prepared by etching the CuO/CeO₂/Ag₂O mixed oxides in a HCl aqueous solution. The removal of CuO resulted in the formation of ultrafine nanoporous CeO₂, inside which Ag nanoparticles were formed in situ by combining a chemical reduction. The sizes of pore channel and ligament were less than 20 nm. The test results revealed that the nanoporous CeO₂-Ag catalysts exhibited an enhanced catalytic activity toward the oxidation of CO. The catalytic activity was attributed to the enhancement of interfacial interaction between CeO₂ ligament and Ag particle.