The influence of reduction temperature (450-900 degrees C) on the catalytic activity of Ce0.70La0.20Ni0.10O2-delta sample during methane dry reforming reaction to synthesis gas has been studied. The activity of the sample, prepared by combustion synthesis, has been evaluated at 750 degrees C under increasing gas hourly space velocity (from 26400 to 105600 h(-1)) for 50 h of stream. H-2-reduction of the sample at 450 degrees C induces, during reaction, large amount of carbon deposition (21-27%) that increases by increasing the gas hourly space velocity (GHSV), as revealed by TPO analysis on spent catalysts. Stable activity was revealed after reduction at 750 and 900 degrees C under a GHSV of 26400 h(-1). The catalytic activity of the reduced samples, by apparent specific activity, increases by increasing the Ni particles size and by increasing the fraction of Ni sites revealed by H-2-TPD peak at high temperature. The catalytic behavior has been discussed on the basis of the samples characterizations derived from X-ray diffraction, UV-vis diffuse reflectance spectroscopy, H-2-programmed reduction (TPR) and desorption (TPD), CO pulse chemisorption, X-ray photoelectron spectroscopy (XPS) and Scanning Electron Microscopy-Energy dispersive X-Ray (SEM/EDX). (C) 2017 Elsevier B.V. All rights reserved.