A new Gd-promoted nickel catalyst for methane conversion to syngas and as an anode functional layer in a solid oxide fuel cell

摘要

The effect of lanthanide promoters on a Ni-Al_2O_3 catalyst for methane partial oxidation, steam reforming and CO_2 reforming at 600-850℃ is systematically investigated. The promoters include La_2O_3, CeO_2, Pr_2O_3, Sm_2O_3 and Gd_2O_3. GdNi-Al_2O_3 shows comparable catalytic activity to LaNi-Al_2O_3 and PrNi-Al_2O_3 but higher activity than CeNi-Al2O_3 and SmNi-Al_2O_3 for all three reactions. The O2-TPO results show that GdNi-Al_2O_3 possesses the best coke resistance among those tested. It also displays good stability at 850℃ for 300 h. Raman spectroscopy indicates that the addition of lanthanide promoters can reduce the degree of graphitization of the carbon deposited on Ni-Al_2O_3. The GdNi-Al_2O_3 is further applied as an anode functional layer in solid-oxide fuel cells operating on methane. The cell yields peak power densities of 1068,996 and 986 mWcm~(-2) at 850℃, respectively, for operating on methane-O_2, methane-H_2O and methane-CO_2 gas mixtures, which is comparable to operating on hydrogen fuel. GdNi-Al_2O_3 is promising as a highly coking-resistant catalyst layer for solid-oxide fuel cells.