The sonochemical synthesis and characterization of highly active and stable Ni nanoparticles supported on TiO2 as a CO methanation catalyst for the production of synthetic natural gas are reported. The catalyst synthesized by sonication showed higher activity for CH4 formation than the catalyst synthesized via the conventional wet impregnation method. The activation energy was found to be 79 and 94 kJ mol-1 for the catalyst synthesized with sonication and wet impregnation method, respectively. The combined results of x-ray photoelectron spectroscopy and x-ray diffraction show that the enhancement in activity of the sample synthesized by sonication method is due to partial substitution of Ni in TiO2 lattice. This creates oxide vacancies and facilitates hydrogen adsorption and spillover from nickel to support. H2- temperature-programmed reduction study corroborates the intimate contact of Ni with support, thus rendering strong metal support interactions. The mechanism involving Langmuir-Hinshelwood kinetics with hydrogen-assisted CO dissociation was used to correlate experimental data. © 2013 American Institute of Chemical Engineers.