Synthesis of Co/Ni Unitary‐ or Binary‐Doped CeO2 Mesoporous Nanospheres and Their Catalytic Performance for CO Oxidation

In this paper, pure ceria, ceria doped with transition metal ions (Co2+, Ni2+), and Co/Ni binary-doped ceria mesoporous notched hollow nanospheres were prepared from a one-step solvothermal synthesis. By introducing metal ions, the composition can be freely manipulated. The morphologies and crystalline structures of the products were characterized in detail by XRD, TEM, SEM, and HRTEM. The surface compositions of the as-prepared ceria samples were detected by Raman spectroscopy, energy-dispersive X-ray spectrometry (EDS), and X-ray photoelectron spectroscopy (XPS). The surface areas and pore-size distributions of the as-obtained doped ceria mesoporous nanospheres were investigated by N2 adsorption–desorption measurements. Temperature-programmed reduction measurements under H2 (H2-TPR) showed the better reduction behavior of the doped ceria samples. Preliminary CO catalytic oxidation experiments indicated that the doped ceria samples showed strikingly higher catalytic activity, owing to the intrinsic surface defects of the samples. In addition, the as-obtained ceria nanospheres can be used as excellent supports for gold nanoparticles to remove CO by catalytic oxidation; therefore, they demonstrate a promising potential in environmental remediation. This one-step synthesis is a versatile approach and it could be extended to other binary or ternary metal oxide systems.