Inhibitor, co-catalyst, or intermetallic promoter? Probing the sulfur-tolerance of MoOx surface decoration on Ni/SiO2 during methane dry reforming

Abstract

Abstract As for the application of CH4\xa0dry reforming\xa0(DRM), primary concern was focused on solving the deactivation of\xa0supported Ni catalysts\xa0caused by\xa0particle sintering and coke accumulation, while little attention has been paid to negative effect resulted from sulfur poisoning. The present work gave an account of the effect of H2S on the DRM over MoOx decorated Ni/SiO2 catalyst. It showed that Mo modified samples presented better sulfur resistance performance. Moreover, the interesting discovery was that different forms of Mo species were worked as special roles during H2S-induced DRM. The suitable amount of Mo, involved as the inhibitor and/or the co-catalyst, could increase the competitive adsorption capacity for H2S, thus slowing down sulfuration rate of the active Ni sites. Meanwhile, as for the specially pre-reduced catalysts, the formed intermetallic metal of Ni-Mo component contributed to a continuous sulfur-adsorption behavior for H2S, thus protecting the active Ni sites from sulfuration. Consequently, probing the sulfur-tolerance of MoOx\xa0surface decoration on Ni/SiO2\xa0could elucidate some useful keys for the development of high sulfur-resistance catalysts, which, as a consequence, would be adequate catalysts for the H2S-induced DRM process.