基于原位合成的Ni/Mg@MCM-41上的CO2甲烷化研究

通过原位引入Mg一步法合成了Mg@MCM-41复合介孔材料,并将其作为载体制备了高性能Ni基CO_2甲烷化催化剂。通过BET、XRD、TEM、CO_2-TPD、TG等手段对催化剂进行了表征分析,着重比较了Mg/Si物质的量比对于催化剂特性的影响。结果表明,当Mg/Si物质的量比为0.05时能够在不破坏孔道结构的前提下显著增加催化剂上的碱性位,有效地提高了催化剂对CO_2的吸附和活化,从而促进CO_2甲烷化反应过程中反应物的转化。实验所制得的催化剂均具有较好的热稳定性和催化反应活性,其中,Ni/0.05Mg@MCM-41在CO_2甲烷化反应表现出最优的催化性能,在320℃,1 MPa的条件下,CO_2转化率和CH_4选择性分别高达84.3%和97.8%。

CO2 methanation over Ni/Mg@MCM-41 prepared by in-situ synthesis method

A series of xMg@MCM-41(x=0, 0.05, 0.1) functional mesoporous materials were synthesized by a novel in-situ one pot method and then were used as support for Ni based catalysts. The results of XRD and TEM show that when the amount of Mg/Si (molar ratio) is 0.05, Mg@MCM-4 with a regular and ordered mesoporous structure is synthesized where Mg is introduced into the framework of MCM-41. Introducing Mg into the framework of the support can significantly enhance the basic properties of the catalyst, thus promoting the adsorption and activation of CO₂. The catalysts prepared in the experiments all have good thermal stability and catalytic activity. Among them, Ni/0.05Mg@MCM-41 shows the best low temperature reaction activity in the CO₂ methanation reaction.