Remarkable activity and stability of Ni catalyst supported on CeO2-Al2O3 via CeAlO3 perovskite towards glycerol steam reforming for hydrogen production

Abstract

The effects of CeO2-Al2O3 mixed oxide preparation methods on the physical and chemical properties of CeO2-Al2O3, and the catalytic performance toward glycerol steam reforming (GSR) over the CeO2-Al2O3-supported Ni catalysts were investigated. Three CeO2-Al2O3 supports were prepared by a single-step sol-gel (SS) of ceria and alumina precursors, followed by the impregnations of ceria precursors on both a xerogel Al2O3 (IS) and a commercial Al2O3 (IC). The characterization techniques used were N2 adsorption-desorption, H2-chemisorption, XRD, H2-TPR, NH3-TPD, XANES, XPS and TGA. The sol-gel derived supports generate not only a well-developed mesoporous structure, but also the incorporation of the Ce species into the Al2O3 structure forming CeAlO3 perovskite. This formation suppresses the interaction between Ni and Al2O3, thereby increasing the number of active and Brønsted acid sites to improve the bifunctional metal-acid properties of Ni/CeO2-Al2O3 in the hydrogenolysis and dehydrogenation-dehydration of condensable intermediates that produce more H2. The formation of CeAlO3 is remarkably promoted by the single-step sol-gel preparation method, and the catalyst supported on the SS-derived oxide exhibits excellent activity and strong resistances to coke formation, phase transformation, and nickel sintering.