Partial Oxidation of Methane to Syngas over Ni/Al2O3 Catalysts Prepared by a Modified Sol-Gel Method

Ni/Al2O3 catalysts were prepared by the impregnation method (IM), sol-gel method (SG), and modified sol-gel method (MSG). The effects of the preparation methods on the catalytic perfortnances in the partial oxidation of methane (POM) to syngas were investigated. The catalysts were characterized by N-2-adsopriton, X-ray diffraction (XRD), temperature-programmed reduction (TPR), thermal gravimetric analysis (TGA), and temperature-programmed oxidation (TPO) in order to investigate the textural properties, crystalline structures, reduction properties, and carbon deposition behaviors. The results revealed that the modified SG method improved the specific surface area and pore volume. The catalytic performance of the Ni/Al2O3 catalysts was improved by the MSG method. Moreover, the structural stability in the reaction and the resulting resistance to carbon deposition was significantly enhanced by the MSG method. It was proposed that the high resistance to carbon deposition of catalysts resulting from the MSG method was related to the inhibition of Ni particles growth in the reaction of POM and the formation of the active amorphous carbon species.