Effect of Ni Loading and Ce_xZr_(1-x)O_2 Promoter on Ni-Based SB A-15 Catalysts for Steam Reforming of Methane

摘要

A series of Ni/SBA-15 catalysts with Ni contents ranging from 5wt% to 20wt% as well as 10wt%Ni/10wt%Ce_xZr_(1-x)O_2/SBA-15 (x=0, 0.5, 1) were prepared. The structures of the catalysts were characterized using XRD, TPR, TEM and BET techniques. The catalytic activities of the catalysts for steam reforming of methane were evaluated in a continuous flow microreactor. The results indicated that both the Ni/SBA-15 and the Ni/Ce_xZr_(1-x)O_2/SBA-15 catalysts had good catalytic activities at atmospheric pressure. The 10wt%Ni/SBA-15 catalyst exhibited excellent stability at 800℃ for time on stream of 740 h. After the reaction, carbon deposits were not formed on the surface of the catalyst. There existed a regular hexagonal mesoporous structure in the Ni/SBA-15 and the Ni/Ce_xZr_(1-x)O_2/SBA-15 catalysts. The nickel species and the Ce_xZr_(1-x)O_2 component were all confined in the SBA-15 mesopores. The Ce_xZr_(1-x)O_2 could promote dispersion of the nickel species in the Ni/Ce_xZr_(1-x)O_2/SBA-15 catalysts.