Sn改性铜基催化剂用于合成气间接制乙醇的反应性能研究

Study on reaction performance of Sn-modified copper-based catalyst for indirect production of ethanol from syngas

采用共沉淀法和等体积浸渍法制备了质量分数分别为0.1%、0.6%、1.2%的Sn改性CuZnAl催化剂,并对其进行了XRD、H_(2)-TPR、N_(2)吸/脱附、TEM等表征。通过构建三级串联催化体系,重点研究了Sn对CuZnAl加氢组分和耦合催化性能的影响。结果表明,Sn的引入可以与Cu形成合金,加强与铜物种的相互作用,促使铜物种更难被还原。适当的Sn负载量对整个耦合反应至关重要,其中0.1%Sn负载量的CuZnAl催化剂不仅明显抑制了水煤气反应,还提高了乙醇选择性和催化体系的稳定性。但随着Sn负载量的继续升高,铜物种的分散性会减弱,当Sn负载量为1.2%时反而会促进水煤气反应并增加烃类的选择性,不利于目标反应。

Sn-modified CuZnAl catalysts with mass fraction of 0.1%,0.6% and 1.2% were prepared by co-precipitation and equal volume impregnation,and characterized by XRD,H_(2)-TPR,N_(2) adsorption/desorption and TEM.By constructing a three-stage tandem catalytic system,the effects of Sn on the hydrogenation components and coupling catalytic performance of CuZnAl were studied.The results show that,the introduction of Sn can form an alloy with Cu,strengthen the interaction with copper species,and make it more difficult for copper species to be reduced.Proper Sn loading is very important for the whole coupling reaction.CuZnAl catalyst with 0.1% Sn loading not only significantly inhibits the water gas reaction,but also improves the ethanol selectivity and the stability of the catalytic system.However,with the continuous increase of Sn loading,the dispersion of copper species will weaken.When the Sn loading is 1.2%,it will promote the water-gas reaction and increase the selectivity of hydrocarbons,which is not conducive to the target reaction.