A study of deactivation by H₂S and catalytic performance of nickel phyllosilicate for direct biogas methanation

In this study, novel Ni phyllosilicates were synthesized by a modified one-step silica sphere method and employed as H₂S mitigation materials for the process. The performance test was performed in a dual catalytic bed system using a simulated biogas with H₂S. The optimized Ni phyllosilicate (NS315) shows excellent performance, achieving threefold CH₄ yield (Y_CH4, 63.2%) higher than the Ni/CeO₂ methanation catalyst (Y_CH4, 17.9%), while its H₂S mitigation exhibits impressive performance with a prolong operating time from 4 to 6 h under 200 ppm H₂S. The basicity of Si–OH on phyllosilicate surface greatly enhances the adsorption capacity with higher coverage of acid H₂S gas. Moreover, the enhanced metal-support interaction arising from Ni–O–Si bonds in the Ni phyllosilicate further improves the stability of the material. This work highlights a new feature of Ni phyllosilicates as a sacrifice bed material for H₂S mitigation in direct methanation of raw biogas.