K_2CO_3含量对Ni-Cu-Mn-K/Al_2O_3水煤气变换催化剂结构和性能的影响

Effects of K_2CO_3 Content on Structure and Properties of Ni-Cu-Mn-K/Al_2O_3 Catalysts for Water-Gas Shift Reaction

以γ-Al2O3为载体,采用等体积浸渍法,制备了不同K2CO3含量的Ni-Cu-Mn-K/Al2O3水煤气变换催化剂,采用低温N2吸附、XRD、TPD和TPR,考察了K2CO3含量对催化剂结构和性能的影响。结果表明:K2CO3的加入使催化剂的还原温度有所提高,适量的K2CO3能增加活性组分的电子密度,从而增强其给电子活化CO的能力,提高催化剂的活性。但过量的K2CO3使得催化剂比表面积和孔容降低,且导致催化剂对CO吸附过强,催化活性降低。当Ni-Cu-Mn-K/γ-Al2O3催化剂中K2CO3的添加量为7.5%时,且催化剂经530℃耐热15h后,在350℃时水煤气变换反应中CO转化率达62.29%。

A series of Ni-Cu-Mn-K/Al2O3 multi-metal component catalysts with different K2CO3 loading used for Water-Gas Shift Reaction were prepared by impregnation method. The effect of K2CO3 content on the structure and property of the catalysts was studied by N2 physical adsorption, XRD, HE-TPR and CO-TPD techniques. The results show that the addition of a certain K2CO3 could result in increase of the reduction temperature, the electromdensity of the activity compositions and the ability of electron donation for activating CO in the catalysts, thus enhancing their catalytic activity. However, the excess K2CO3 would lead to the decrease of surface area and pore volume, and lead to the increase of CO adsorption ability, thus resulting in the decrease of catalytic activity. After Ni-Cu-Mn-K/ Al2O3 catalyst with K2CO3 content of 7.5% calcined at 530 ℃ for 15 h, its CO conversion is 62.29% for water gas shift reaction at 350 ℃.