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

[Display omitted] •The effect of H2S on DRM over MoOx decorated Ni/SiO2 was studied.•Mo modification could increase competitive adsorption capacity of H2S.•The formed intermetallic metal of Ni-Mo protected Ni sties from sulfuration.•MoOxsurface decoration would be useful for the H2S-induced DRM process. As for the application of CH4dry reforming(DRM), primary concern was focused on solving the deactivation ofsupported Ni catalystscaused byparticle 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 MoOxsurface decoration on Ni/SiO2could 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.