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 metal particle surfaces, thereby geometrically destroying large ensembles of metal atoms necessary for carbon deposition. In addition, it has been suggested that sites at the metal-TiOx interface are created which promote catalyst activity. To further elucidate the role of metal-support interactions, CO2 reforming of CH4 has been investigated over a series of SiO2- and TiO2-supported transition metals. Turnover frequencies for CO formation were found 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 support can participate in the activation of both CH4 and CO2, and that CHxO species can be formed during CH4 adsorption on TiO2-supported transition metals after reduction in H-2 at 773 K. (C) 1999 Elsevier Science B.V. All rights reserved.