CH₄ reforming with CO₂ over superfine Ni-based catalysts: I. Effects of preparation methods on structure and TPR of catalysts

The effects of preparation methods on structure and TPR profiles of Ni-based catalysts for CH₄ reforming with CO₂ were investigated by means of BET, XRD, XPS, IR and TPR techniques. The superfine NiO-Al₂O₃ and NiO-La₂O₃-Al₂O₃ aerogel catalysts prepared by sol-gel and supercritical drying (SCD) techniques possess very large surface area, low apparent density and well-defined pore size distribution, compared with the ones prepared by conventional impregnation. The interaction between components in aerogel catalysts is strong enough and well distributed, leading to the formation of NiAl₂O₄ spinal at lower temperature. The stronger adsorptive power and much more surfacial defects and atoms were observed in aerogel catalysts, which can be attributed to the properties of nano-particles. The binary aerogel catalyst is better than the one with superfine alumina as support, and the ternary aerogel catalyst is better than the binary one owing to the addition of La₂O₃. Therefore, the sol-gel and SCD techniques are also favorable for preparation of multiple component Ni-based catalysts suitable for CH₄ reforming with CO₂.