Nickel-based catalyst precursor prepared via microwave-induced combustion method: Thermodynamics of synthesis and performance in dry reforming of CH4

Abstract

Nickel-based catalyst precursor for dry reforming of methane was successfully prepared by a selfombustion method. Three different amino acids: urea, glycine and citric acid were tested as fuels in the redox reaction with metal nitrates. For each fuel, a thermodynamic modeling of the combustion reaction was performed. The samples were characterized by X-ray diffraction (XRD), Thermogravimetric analysis (TG), Scanning electron microscopy (SEM), Attenuated total reflectance - Fourier transform infrared (ATR-FTIR) spectroscopy and Temperature-programmed reduction (TPR). XRD data confirmed the presence of several crystalline phases in the as-prepared powders. The sample prepared with citric acid showed very low crystallinity when compared to the other samples. It was found that the heat release rate of the self-combustion is the determinant factor of the crystallization, and it is fuel dependent. SEM results suggest that the distribution and average particle size of as-prepared powders can be controlled by the appropriate selection of the fuel. Further calcination of these samples at 800 C/4h led to the crystallization of perovskite-type structure LaNiO3. Nanostructured Ni0/La2O3 obtained after reduction of LaNiO3 precursor showed high catalytic activity in dry reforming of methane.