Catalytic decomposition of methane over cerium-doped Ni catalysts

Si-Ce-O mixed solids (50, 30, 10 and 5, Si/Ce molar ratio) were prepared by using Ce(NO₃)₃.6H₂O as cerium source, tetraethyl orthosilicate (TEOS) as Si precursor and cetyltrimethylammonium bromide (CTABr) as synthesis template. The Ni catalysts were prepared by impregnation of the supports using Ni-acetilacetonate (30 wt.% Ni) as Ni source. The samples were characterized by: X-ray diffraction, temperature-programmed reduction (TPR), and TEM. The nickel reduction degree decreased with the addition of cerium, even in low concentration. When methane was decomposed over all the catalysts only hydrogen was obtained as a gaseous product. The addition of cerium brought about a significant increase in stability compared with Ni/SiO₂ catalyst. These preliminary results indicated that CeO ₂ addition improves the dispersion of Ni particles leading to a better distribution of deposited carbon and increasing the lifetime of Ni particles.