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

• Published in: Process safety and environmental protection 2024-03, Vol.183, p.244-259
• Main Authors: Chen, Li-Wei, Ng, Kim Hoong
• Format: Article
• Language: English
• Subjects: CO2 utilization; Greenhouse gases; Morphological-controlled catalyst; Syngas; Tremella-like
• ISSN: 0957-5820; 1744-3598
• DOI: 10.1016/j.psep.2024.01.004

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 monometallic Ni/SiO2 catalyst was hydrothermally synthesized herein, realizing 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 diffusion of reactants/products gas to/from catalytic surface, thus augmenting its 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 using 90 min in-situ oxidative regeneration. Mechanistic study coupling sorptive investigation, ex-situ XRD, and SEM 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. [Display omitted] •Tremella-like Ni/SiO2 is highly active toward dry reforming of methane (DRM).•Tapered end of Ni-petal suppresses coke formation during DRM reaction.•Thick Ni base permits robust metal-support interaction for improved stability.•Open structure of Ni/SiO2 improves the accessibility of reactants and products.