Hydrothermally synthesized tremella-like monometallic Ni/SiO2 for effective and stable dry reforming of methane (DRM) to syngas

Despite its activity, monometallic Ni-catalyst is highly susceptible to coke deposition and sintering in catalyzing dry reforming of methane (DRM). To counter these, a novel tremella-like Ni/SiO2 catalyst was hydrothermally synthesized herein, imparting excellent activity, outstanding coke inhibition and robust structural stability for a durable DRM reaction. Functionality-speaking, the tapered ends of Ni-petals, sized at 8-15 nm, permit high DRM activity with suppressed coke formation while its thicker base spatially prevents Ni-sintering during high temperature reaction. Meanwhile, the open structure of catalyst resulting from such tremella-like structure also enhances the accessibility of reactants/products gas to catalytic surface, thus improving overall activity for DRM. With merely 5 wt.% Ni incorporated, CO2 and CH4 conversions of ~90% could be attained, with only ~15% activity drop after 75 h of DRM. Full restoration of activity could facilely be attained in just 90 min in-situ oxidative regeneration. Mechanistic study coupling ex-situ XRD, SEM and sorptive investigation reveals the pronounced adsorption tendency of CH4 over those of CO2, H2 and CO, confirming the adherence of DRM to Eley-Rideal reaction model in current study. Significantly, this study provides a new morphological-controlled strategy to conveniently impart excellent coke-inhibiting and sintering-resisting capability to monometallic Ni-catalyst.