Evidence for the participation of surface nickel aluminate sites in the steam reforming of methane over nickel/alumina catalysts

The specific activities of various Ni Al₂O₃ catalysts for the reaction of CH₄ with H₂O have been obtained and have been shown to vary markedly with catalyst preparation and to differ considerably from the specific activities of pure nickel. This has been explained by suggesting that the unreduced catalysts contain surface nickel aluminate phases which, on reduction, give monodispersed nickel atoms closely associated with alumina sites in addition to metallic crystallites arising from the reduction of nickel oxide. The results of exchange experiments using deuterium and H₂¹⁸O are presented in support of the suggestion that the monodispersed nickel atoms probably participate in the CH₄ + H₂O reaction.