Preparation of mesoporous nanocrystalline Ni-MgAl۲O۴ catalysts by sol-gel combustion method and its applications in dry reforming reaction

چکیده مقاله

A surfactant assisted sol-gel combustion method was employed for the synthesis of mesoporous nanocrystalline magnesium aluminate spinel with the high specific surface area as support for nickel catalysts in the dry reforming reaction. The prepared samples were characterized by X-ray diffraction (XRD), N2 adsorption (BET), Fourier transform infrared spectroscopy (FTIR), temperature programmed reduction and oxidation (TPR, TPO) techniques. The effects of several process parameters such as metal nitrate to citric acid (MN/CA) and citric acid to PEG (polyethylene glycol), (CA/PEG) ratios, pH and calcination temperature were investigated. The obtained results showed that the addition of surfactant has a significant effect on the surface area. The XRD analysis showed that the single-phase MgAl2O4 was formed at 700 °C. The results revealed that the catalyst with 10 wt.% Ni content and 97.1 (m2 g−1) surface area and particle size of 13.7 (nm) exhibited high CH4 and CO2 conversions. In addition, CO2 conversion was higher than the CH4 conversion in all temperatures because of the occurrence of reverse water gas shift reaction.