Steam reforming of methanol over x% Cu/Zn-Al 400 500 based catalysts for production of hydrogen: Preparation by adopting memory effect of hydrotalcite and behavior evaluation

摘要

A novel catalyst for hydrogen production from the catalytic process of methanol steam reforming could play an important role in hydrogen production to be used as a feed for fuel cell. Our study focuses on the preparation of copper supported on calcined hydrotalcite catalysts using the memory effect of zinc-aluminum hydrotalcite. Zinc-aluminum was calcined at 400 ℃ and dipped in a copper nitrate aqueous solution. The steam reforming of methanol was studied in a fixed-bed reactor under mild conditions and a reaction temperature range of 200-350 ℃. The catalysts were characterized by XRD, SEM, TPR, chem-isorption N_2O, TG/DTA, IR and N_2 adsorption techniques in order to identify their physical and chemical properties. The results evince the regeneration and the reconstruction of the layered structure that have a positive influence on the interactions between support and copper species. After activation by calcination at 500 ℃, the solids copper/zinc-aluminum (Cu/Zn-Al 400 500) showed an interesting mixed oxides and were tested in the reaction of methanol steam reforming. The 10% Cu/Zn-Al 400 500 exhibits the best catalytic activity about 75.44% of H_2 yield with 51.87% of methanol conversion at 250 ℃. Methanol conversion was found to be a strong function of catalyst reducibility and copper concentration. Also, reaction temperature depended strongly on the amount of Cu_2O formed in the activated catalyst.