A new explanation for the carbon deposition and elimination over supported Ni, Ni-Ce and Ni-Co catalysts for CO2-reforming of methane

The influence of the addition of CeO2 or Co3O4 to Ni-based catalysts on carbon deposition by CH4 and carbon elimination by CO2 was studied with a pulse reaction as well as BET, TGA, XPS and hydrogen chemisorption techniques. It was found that addition of the CeO2 decreased the carbon deposition activity of CH4 and increased the carbon elimination ability of CO2, which could be explained by the interaction between the metal (Ni) and n-type semiconductor (CeO2). However, the addition of the Co3O4, which was transformed to Coo during the reaction, accelerated carbon deposition by CH4 and resisted carbon elimination by CO2. A novel model of carbon deposition/carbon elimination over Ni-based catalysts has been proposed.