Catalytic Activities and Coking Characteristics of Oxides-Supported Ni Catalysts for CH₄ Reforming with Carbon Dioxide

Catalytic activities and deactivation characteristics of oxides-supported nickel catalysts for the reaction of methane reforming with carbon dioxide were investigated. The dynamic carbon deposition on various nickel catalysts was also studied by a thermogravimetric method. Among the catalysts prepared, Ni/La 2 O 3, Ni/α-Al 2 O 3, Ni/SiO 2, and Ni/CeO 2 showed very high CH 4 and CO 2 conversions and moderate deactivation whereas Ni/MgO and Ni/TiO 2 had lower conversions when the Ni reduction was conducted at 500 °C. When Ni/MgO catalyst was reduced at 800 °C, it exhibited not only comparable conversions of CH 4 and CO 2 with other active catalysts but also much longer period of stability without deactivation. The amount of carbon deposited in Ni-based catalysts varied depending on the nature of support and followed the order of Ni/La 2 O 3 > Ni/α-Al 2 O 3 > Ni/SiO 2 > Ni/MgO > Ni/CeO 2 at 700 °C. The carbons formed on the catalyst surface showed different structural and chemical properties, and these in turn affected the catalytic activity of the catalysts.