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用TPR和XPS技术对比研究了添加镧对Ni/α-Al_2O_3天然气蒸汽转化催化剂还原性能的影响。实验结果表明,不论添加方式如何,加有镧的催化剂都不同程度地比单浸镍催化剂的初始还原温度和峰顶温度(Tm)要低些,并且还原速度快些。根据氧化镍还原的成核模型(Nucleation model)和“掺杂”促进还原的机理,结合添加镧后对催化剂镍晶粒大小的影响,对上述现象进行了解释。
The effect of adding lanthanum on the reduction performance of Ni / α-Al_2O_3 natural gas steam reforming catalysts was compared with TPR and XPS techniques. The experimental results show that, regardless of the method of addition, lanthanum-added catalysts are somewhat lower than the initial reduction temperature and the peak top temperature (Tm) of the single-dipped nickel catalysts, and the reduction rate is faster. According to the nucleation model of NiO reduction and the mechanism of reduction by “doping”, the above phenomenon is explained by the combination of the effect of adding lanthanum on the size of Ni catalyst.