Ni/CeO2-Al2O3 catalysts for methane thermo-catalytic decomposition to COx-free H2 production

The effect of ceria addition to alumina on the catalytic performance of the active NiO particle has been investigated during methane decomposition to CO/CO2 free H2 production. The CeO2-Al2O3 supports with different CeO2 loading were prepared by co-precipitation and loaded with 50 wt% Ni by incipit wetness impregnation method. The catalysts were characterized by XRD, HRTEM, BET, TPR and Raman spectroscopy. The results revealed that the catalytic activity was strongly depended on the ceria content in the catalyst. The highest methane decomposition to H2 was achieved over the Ni/Ce25-Al75 catalyst. TEM images illustrated that, various kinds of carbon nano-structured materials were obtained on the catalyst surface according to the Ce content. Carbon nanofiber (CNF) and graphene films (GF) were formed on the surface of Al2O3, Ni/Ce25-Al75, Ce50-Al50 and Ce75-Al25 supported Ni catalysts. While only multi-walled carbon nanotubes (MWCNT) was obtained on Ni/Ce catalyst. The formation of Ni-O-Ce solid solution induced highly dispersed Ni particles with relatively small sizes, leading to the growth of filamentous carbon.