The promoting influence of nickel species in the controllable synthesis and catalytic properties of nickel-ceria catalysts

In this paper, a series of well-dispersed nickel-ceria catalysts with high surface area were successfully fabricated using a simple solvothermal approach and characterized by XRD, TEM, EDS, N-2-sorption, Raman and TPR techniques. The results show that the amount of nickel species can have an impact on the morphology of the nickel-ceria catalysts, i.e. the hollow structure, particle size and porous structures. The prepared nickel-ceria samples (with the atomic ratio Ni : Ce (At% (Ni/Ce)) at approximately 6.58%) exhibit high catalytic performance in carbon monoxide (CO) oxidation with 100% conversion at 200 degrees C. The XRD, Raman, XPS and H-2-TPR data confirm that the nickel species are the main promoting factor in the catalysis, including the doped nickel species, highly dispersed free NiO and the interfacial Ni-[O]-Ce structures. Further, the as-prepared nickel-ceria catalysts show high stability in the catalysis.