The objective of the present work is the study of CH4 tri-reforming process (simultaneous carbon dioxide reforming, steam reforming and oxygen reforming) that can contribute to the CO2 abatement producing synthesis gas with the desiderate H-2/CO ratio. A series of Ni-CeO2 catalysts with different La loadings is prepared by combustion synthesis and tested as catalysts in CH4 Tri-reforming reaction at 800 degrees C under atmospheric pressure with a GHSV of 30,000 h(-1). It has been found that during tri-reforming reaction the activity of Ni-ceria catalysts can be enhanced by an appropriate amount of La doping (10 at.%), the CH4 and CO2 conversion increases from 93% and 83% to 96% and 86.5%, respectively. The activity enhancement appears to be related to synergic effect of nickel-lanthana-surface oxygen vacancies of ceria via interfacial active sites that contribute to increase the nickel dispersion and create a basic site distribution on the surface able to interact with CO2. (C) 2011 Elsevier B.V. All rights reserved.