The Ni/SiO2 catalysts were prepared with nickel citrate precursor by using incipient-wetness impregnation method, characterized by FT-IR, UV-Raman, TG-DTA, XRD, HR-TEM and H-2-TPR, and tested in the reaction of methane reforming with CO2 and O-2 to produce syngas. The highly-dispersed Ni particles (similar to 7 nm) on support SiO2 were observed by TEM. FT-IR results indicated that there existed interaction between-nicketcitrate precursor and SiO2. H-2-TPR results demonstrated that, this interaction was enhanced by calcination at high temperature to form strong NiO-SiO2 interaction, and the strong interaction was recovered after repeating oxidation-reduction-oxidation cycle at 700 degrees C. As a result, the Ni/SiO2 catalysts showed a good activity and super stability without sintering of nickel particles during 36 h reaction on stream. (C) 2013 Elsevier Ltd. All rights reserved.