Enhanced performance and selectivity of CO2 methanation over phyllosilicate structure derived Ni-Mg/SBA-15 catalysts

Ni and Ni-Mg phyllosilicate mesoporous SBA-15 catalysts were successfully prepared via ammonia evaporation (AE) method as evidenced by XRD, H-2-TPR, TEM, FTIR and EXAFS fitting results. The catalysts derived from phyllosilicate structure exhibit superior catalytic performance in CO2 methanation as compared to catalyst prepared via wetness impregnation (WI) method due to enhanced metal-support interaction and the presence of weakly basic sites provided by surface hydroxyl groups. Incorporation of Mg into phyllosilicate structure with optimum 5 wt% is also found to increase medium basic sites, which can promote monodentate formate formation as identified by DRIFTS analysis and improve CO2 methanation activity at lower temperatures. Additionally, the turnover frequency of CO2 conversion can be well correlated with the concentration of basic sites. The strong metal-support interaction derived from phyllosilicate structure along with confinement effect of SBA-15 can suppress metal sintering, resulting in good stability.

Automated summary

Ni and Ni-Mg phyllosilicate mesoporous SBA-15 catalysts prepared via ammonia evaporation (AE) method exhibit superior catalytic performance in CO2 methanation compared to catalysts prepared via wetness impregnation (WI) method, due to enhanced metal-support interaction and weakly basic sites provided by surface hydroxyl groups. Incorporation of Mg into phyllosilicate structure increases medium basic sites, promoting monodentate formate formation and improving CO2 methanation activity. Additionally, the turnover frequency of CO2 conversion is correlated with the concentration of basic sites, and the strong metal-support interaction and confinement effect of SBA-15 can suppress metal sintering, ensuring good stability.