Sn修饰的Ni/γ-Al2O3催化乙二醇液相重整制氢

摘要

A series of NiSn/γ-Al2O3 catalysts with different mole ratio of Ni to Sn were prepared by wet impregnation and used in the liquid-phase reforming of ethylene glycol to hydrogen.The experimental results indicated that the as-prepared catalyst with the mole ratio of 42 showed the excellent conversion of ethylene glycol to gas and selectivity to H2,65.4％ and 88.4％ respectively.The Sn modification for Ni/γ-Al2O3 catalysts could effectively promote the selectivity to H2,but the catalytic activity was first enhanced and then declined with increasing the amount of Sn.The catalysts were characterized by means of XRD,SEM and TEM.The results show that an appropriate amount of Sn could improve the dispersion of Ni on the catalysts.The active surface area of NiSn-42/γ-Al2O3 catalyst is more than those of the other catalysts,which can account for its high activity.The stability of NiSn-42/γ-Al2O3 was researched.The results indicated that the activity of the catalyst could keep 34％ of the initial activity after the reaction reaching stable state.The deactivation of NiSn-42/γ-Al2O3 catalyst is ascribed to the agglomeration and growth of Ni particles in the reforming process.%通过湿浸渍法制备了一系列Ni与Sn摩尔比不同的NiSn/γ-Al2O3催化剂,将该催化剂用于乙二醇液相重整制氢反应.实验结果表明,Ni与Sn摩尔比为42的NiSn-42/γ-Al2O3催化剂表现出最佳的活性和H2选择性,乙二醇转变为气体产物的转化率和H2选择性分别为65.4％和88.4％;Sn的加入使H2选择性大幅提高；随Sn修饰量的增大,催化剂的活性先增加后降低.表征结果显示,适量Sn修饰到Ni/γ-Al2O3催化剂上能促进Ni的分散；NiSn-42/γ-Al2O3催化剂比其他催化剂具有更大的活性比表面积,因此显示出较佳的活性.同时考察了NiSn-42/γ-Al2O3催化剂的稳定性,实验结果表明,NiSn-42/γ-Al2O3催化剂达到稳态时能保持初活性的34％,重整过程中Ni晶粒的长大和团聚是该催化剂失活的主要原因.