The introduction of organic additives rich in OH groups, such as citric acid, glucose and D-sorbitol, in nickel nitrate impregnation solutions is an efficient way to minify the size of NiO particles. The organic additives promote the wettability of the impregnation solution during solvent evaporation with increasing viscosity continuously, rather than act as ligands to Ni2+. This let Ni species are loaded into the micropores of support KIT-6, which can hinder the aggregation of Ni particles under severe conditions, e.g. thermal treatment at 650 degrees C. These organic additives can insulate the blocks of Ni species from each other during combustion without affecting their reducibility significantly, and result in a fairly high Ni dispersion. This kind of Ni-based catalysts possess excellent CO methanation catalytic performance: high CH4 selectivity (ca. 96% at 350 degrees C), great thermostability and long-term stability.