Double perovskite type catalysts with improved anti-coking and sulfur-resisting performance for diesel reforming

Double perovskite type catalysts with the formula of La₂Co_xFe_2-xO_5+δ, x = 1.5, 1 and 0.5 were synthesized through a modified sol-gel method, which were used for steam reforming of n-hexadecane (a diesel surrogate) containing 50 μg/g sulfur. The prepared catalysts were found to have the significantly improved performance in both anti-coking and sulfur-resisting. Characterizations with XRD, SEM-EDS, XPS, H₂-TPR, thermogravimetric analysis (TGA) and nitrogen adsorption-desorption revealed that the special structure of double perovskite minimized coke formation and improved sulfur resisting, as more oxygen vacancies are generated due to the consumption of surface oxygen, which provides an efficient channel for oxygen diffusion. The effect of different molar ratios of Co to Fe on catalyst activity was also studied, and the catalyst LCF-2 (for x = 1) with a porous structure had the best catalytic activity and stability, achieving a continuous runtime of more than 40 h, better than the single perovskite catalyst LaCo_0.5Fe_0.5O₃.