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研究了以La,Ni氧化物为原料,在高温和氢的气氛下用CaH_2还原制得的LaNi_5,在乙烯加氢反应中的催化性质。发现用此法制备的粉状样品,不需充氢处理和活化,就可以使乙烯在0℃完全转化为乙烷,而且在-78℃也有较高的活性。根据X线衍射,证明此法制得的LaNi_5的体相结构和冶炼法制得的相同;它的高催化活性,XPS能谱和磁性数据,说明在LaNi_5原始表面上有一层活性镍。活性镍的存在,从LaNi_5充氢实验,也得到了进一步证明。因此,此法制得的LaNi_5样品的表面结构和冶炼法不同。
The catalytic properties of LaNi_5, which was prepared by the reduction of CaH_2 under high temperature and hydrogen atmosphere using La and Ni oxides as raw materials, were studied in the hydrogenation of ethylene. It was found that the powdered sample prepared by this method can be completely converted into ethane at 0 ° C without ethane and has high activity at -78 ° C without hydrogen treatment and activation. According to X-ray diffraction, it is proved that the structure of LaNi_5 prepared by this method is the same as that obtained by smelting method. Its high catalytic activity, XPS spectrum and magnetic data indicate that there is a layer of active nickel on the original surface of LaNi_5. The presence of active nickel, LaNi_5 hydrogen charging experiment, has also been further evidence. Therefore, the LaNi_5 sample prepared by this method has a different surface structure and smelting method.