Enhanced Catalytic Performance of (CuO) x /Ce 0.9 Cu 0.1 O 2 Nanospheres: Combined Contribution of the Synergistic Effect and Surface Defects

Copper‐modified ceria catalysts, (CuO) x /Ce 0.9 Cu 0.1 O 2 nanospheres, for low‐temperature CO oxidation were fabricated simply by using the hydrothermal synthesis of Cu‐doped CeO 2 (Ce 0.9 Cu 0.1 O 2 ) nanospheres followed by deposition of CuO over Ce 0.9 Cu 0.1 O 2 . The X‐ray diffraction and electron spectroscopy characterizations demonstrated that the as‐prepared nanospheres were composed of cubic CeO 2 and monoclinic CuO with a typical diameter of around 70 nm. Moreover, the X‐ray photoelectron spectroscopy (XPS) analysis illustrated the coexistence of Ce 4+ /Ce 3+ and Cu 2+ /Cu + redox couples in (CuO) x /Ce 0.9 Cu 0.1 O 2 and H 2 temperature‐programmed reduction (TPR) measurements indicated the excellent reduction behavior of the catalyst. The Raman spectra illustrated the oxygen vacancy in (CuO) 0.3 /Ce 0.9 Cu 0.1 O 2 , and diffuse‐reflectance infrared Fourier transform spectroscopy (DRIFTS) demonstrated the stable existence of Cu + species during CO oxidation. The (CuO) x /Ce 0.9 Cu 0.1 O 2 nanospheres showed excellent catalytic activity toward CO oxidation in normal feed gas (volume ratio of CO/O 2 /N 2 =1:10:89) at ambient temperature. Catalytic tests revealed that the proportion of CuO in the final product has a strong influence on the resultant catalytic activities. The (CuO) x /Ce 0.9 Cu 0.1 O 2 nanospheres hold great application potential as new catalysts for CO oxidation.