The role of metal-support interactions in CO2 reforming of CH4

Prior investigations of CO2 reforming of CH4 have indicated that when TiO2 is used as a support, TiOx species formed during reduction decorate the met al particle surfaces, thereby geometrically destroying large ensembles of m etal atoms necessary for carbon deposition. In addition, it has been sugges ted that sites at the metal-TiOx interface are created which promote cataly st activity. To further elucidate the role of metal-support interactions, C O2 reforming of CH4 has been investigated over a series of SiO2- and TiO2-s upported transition metals. Turnover frequencies for CO formation were foun d to depend on both the support and the %-d character of the metal. In situ DRIFT spectra of CH4 and CO2 adsorption indicate that oxygen from the supp ort can participate in the activation of both CH4 and CO2, and that CHxO sp ecies can be formed during CH4 adsorption on TiO2-supported transition meta ls after reduction in H-2 at 773 K. (C) 1999 Elsevier Science B.V. All righ ts reserved.