Selective CO methanation in H-2-rich gas mixture containing 10 vol.% H2O and 20 vol.% CO2 was investigated over chlorine doped 1.8-46.1 wt.% Ni/CeO2 catalysts. BET, XRD, TEM, EDX microchemical analysis and XPS techniques were used for catalyst characterization. Among the catalysts studied, the 9.1 wt.% Nil CeO2 catalyst with the surface Cl/Ce atomic ratio of 0.15 was the most effective. This catalyst provided the reducing of the CO concentration in H-2-rich gas to less than 10 ppm over a wide temperature interval (250-320 degrees C) keeping the selectivity high (>50%). It was shown that ceria-supported small (20-80 angstrom) nickel-containing particles provided good activity, while stable chlorine species maintained high selectivity of the catalyst. (C) 2013 Elsevier B.V. All rights reserved.