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

Abstract

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, N₂-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 °C. The XRD, Raman, XPS and H₂-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.