Abstract
Interaction between metal and support influence catalytic behavior apparently. To obtain insight into the effect of metal–support interaction (MSI) in the CO2 reforming of CH4, the reaction was studied using pure CeO2 and yttria-doped ceria (YDC), respectively. For comparison, Ni/γ-Al2O3 catalysts were also prepared. The catalysts were characterized by temperature-programmed reduction (TPR), electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS). For Ni/CeO2 and Ni/YDC catalysts, two TPR peak, namely β and γ, were observed. Specific rates (μ mol/(s g cat) ) for the CO2 reforming of CH4 decrease in the order Ni/CeO2 > Ni/5YDC > Ni/10YDC > Ni/20YDC > Ni/40YDC > Ni/γ-Al2O3. Ni/γ-Al2O3 showed appreciable activity for CH4–CO2 reforming. Compare to the Ni/ γ-Al2O3 catalysts Ni/CeO2 showed a dramatic increase in activity is attributed to the creation of new sites in the metal–support interaction region which promote CH4 dissociation, CO2 dissociation and reduction, and subsequent CHxO decomposition, beside activity, a dramatic stability is also fund, combination the result of temperature–programmed hydrogenation of used catalysts and temperature–programmed reduction of fresh catalysts clearly showed that the morphology of Ni on CeO2 surface consisted of very thin platelets and inhibit the rate of deep dehydrogenation of CH4 to carbon, thus improving activity maintenance.