摘要
用TPD,XRD,TPR与微反装置考察了La_2O_3对Ni/α-Al_2O_3系列催化剂的CO吸附性能、镍分散性和还原性及对天然气蒸汽转化反应的活性和稳定性的影响。用XPS及XRD技术探讨了La_2O_3影响催化剂性质的原因。结果表明,La_2O_3能使催化剂镍晶格常数增大,并对镍有吸电子作用,对镍表面有包埋效应,La_2O_3还能提高催化剂的镍分散性、还原性和对CO的化学吸附,La_2O_3对催化剂活性的影响是一个较复杂的多因素的综合,La_2O_3能抑制NiAl_2O_4的生成及催化剂的烧结,从而提高了催化剂的稳定性。
The influence of La2O3 on the CO chemisorption, nickel dispersion, reducibility, activity and stability of natural gas steam reforming catalyst Ni/α-Al2O3 was studied by TPD, TPR, XRD, XPS and micro-reactor. Experimental results indicate that La2O3 can promote the increase of the lattice constant of Ni and the attraction of the electrons of Ni from the catalyst, and also has the embedding effect on Ni surface. La2O3 can also improve the nickel dispersion, the reducibility, the stability and the strength for CO chemisorption of the catalyst. The effect of La2O3 on the activity of the catalyst is a comprehensive effect of many factors.
