Highly Active and Dispersed Ni/Al2O3 Catalysts for CO Methanation Prepared by the Cation–Anion Double-Hydrolysis Method: Effects of Zr, Fe, and Ce Promoters

A highly dispersed nickel catalyst supported on alumina with an NiO loading of 40 wt % has been prepared from Ni(NO3)2·6H2O and NaAlO2 as precursors through a novel cation–anion double-hydrolysis strategy. The product has been tested for its efficacy in CO methanation. The preparation process can be considered as a time-saving and green synthetic technique that does not require the use of a basic precipitation agent. The resulting Ni/Al2O3 catalyst shows a high dispersion of NiO with small particle size (<5 nm), in spite of the high metal loading. Various promoters, namely Zr, Fe, and Ce, were further added to regulate the catalytic properties of the Ni/Al2O3 catalyst, and 40Ni-5Zr/Al2O3 showed the optimal CO methanation activity. The improved catalytic performance could be mainly due to the high degree of Ni dispersion and the abundance of oxygen vacancies, which enhanced the adsorption and dissociation of CO.