State Key Laboratory of Chemical Engineering of Chemical Engineering China University of Science and Technology 200237;
Operando Molecular Spectroscopy and Catalysis Research Laboratory of Chemical and Biomolecular Engineering University 18015;
Department of Instrument Science and Engineering of Electronic Information Engineering Jiao Tong University 200240;
Dalian Research Institute of Petroleum and Petrochemicals 116045;
Nickel–ceria catalyst; Catalyst activation; Crystallinity; Methanation; In situ spectroscopy;