The influence of shell thickness on coke resistance of core-shell catalyst in CO2 catalytic reforming of biomass tar

摘要

The development of catalysts with resistance to sintering and coke deposition is the key to tar cracking during biomass gasification technology. In this work, the core-shell catalysts with mesoporous and microporous silica-coated nickel nanoparticles were prepared for the CO(2 )reforming of toluene as a model compound for biomass tar. The influence of thickness of SiO2 shell layer on catalyst activity, coke and sintering resistance of the catalysts in the CO2 reforming of toluene was explored. Appropriate increasing in the thickness of the silica shell can significantly increase the specific surface area, pore volume and the interaction between core and shell of the catalysts, which can further improve the reactivity and coke resistance ability. However, excessive increase in shell thickness can lead to a drastic decrease in the specific surface area and pore volume of the catalyst, resulting in significant coke deposition. The Ni@SiO2 -4 catalyst showed the highest catalytic activity of toluene conversion of around 50% within 300 min, stability H-2 /CO ratio of 0.25~0.3 and durability of 26 h lifetime in the CO2 reforming of toluene. Overall, the optimization of the silica shell thickness can improve the reactivity and coke resistance ability of Ni@SiO2 .

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