Ce0.70La0.20Ni0.10O2-δ catalyst for methane dry reforming: Influence of reduction temperature on the catalytic activity and stability

Abstract

The influence of reduction temperature (450–900°C) on the catalytic activity of Ce0.70La0.20Ni0.10O2-δ 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°C under increasing gas hourly space velocity (from 26400 to 105600h−1) for 50h of stream. H2-reduction of the sample at 450°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°C under a GHSV of 26400h−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 H2-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, H2-programmed reduction (TPR) and desorption (TPD), CO pulse chemisorption, X-ray photoelectron spectroscopy (XPS) and Scanning Electron Microscopy-Energy dispersive X-Ray (SEM/EDX).