Study of the performance and stability in the dry reforming of methane of doped alumina supported iridium catalysts

Abstract

Iridium catalysts supported on alumina doped with both alkaline (Na and K) and alkaline earth metals (Ba, Ca and Mg) of different concentrations (1, 5 and 10 wt%) were tested in the dry reforming of methane. Supports were characterized by X-ray diffraction, BET surface area, temperature-programmed desorption of CO2 and 2-propanol dehydration. Catalysts were characterized by temperature-programmed reduction, TEM, XPS, cyclohexane dehydrogenation and cyclopentane hydrogenolysis. Dopants were showed to suppress the acidity of the support and the γ-Al2O3 phase remained in the supports doped with Ca, Ba, Na and K after calcination at 800 °C, whereas a phase transition to magnesium aluminate was found for magnesium doped alumina. Stability tests, using long time dry reforming reactions, showed that iridium catalysts have high sintering resistance, their metallic phases being very stable since neither carbon deposition nor sinterization processes were observed.