Hydrogen production from methane decomposition over Ni/CeO2 catalysts

The catalytic behavior of Ni/CeO2 catalysts was investigated for methane decomposition at 773 K. Ni/CeO2 catalysts prepared by impregnation and deposition–precipitation methods showed much higher hydrogen formation rates than that of Ni/CeO2 catalyst prepared by coprecipitation method, which exhibited relatively higher CO formation rate. CH4-TPSR measurements confirmed that CO formation is inevitable during methane decomposition, since the lattice oxygen of ceria could react with the deposited carbons. TEM observations further indicated that the morphologies as well as the reactivities of the deposited carbons are strongly dependent on the interaction degrees between Ni and ceria, which in turn explains the differences in the catalytic activity of the Ni/CeO2 catalysts for methane decomposition. The Ni/CeO2 catalyst prepared by coprecipitation method exhibited rather strong metal–support interaction probably through the formation of Ni–O–Ce solid solution, resulting in much lower hydrogen formation rate and relatively higher CO production.