【摘要】 以化学合成-共沉淀还原法合成了富镧MMNi₅（MM=混合稀土金属）金属间化合物,并对经过充分活化的样品在α相区的吸氢动力学行为进行了研究。在氢初压为10.13～81kPa、温度为313～393K范围内测定了吸氢量与时间、压力、温度的依赖关系。根据动力学数据,计算出吸氢过程的表观激活能为5.02kJ/molH₂,并根据吸氢量与压力的关系,初步确定了在α相区吸氢速率限制性环节为表面过程,吸氢速率方程可表示为:dn/dt=Ke^-E/RT·P₀1/t其中K为常数,P₀为初始氢压,t为反应时间。更多还原

【Abstract】 The cerium-free MMNi₅（MM=mischmetal） alloy prepared by chemical method（coprecipitation-reduction method） has excellent properties for hydrogen storage in comparison to those prepared by metallurgical method. It possesses favorable surface properties and high reactive activity. In this paper the kinetics of hydrogen absorption by well activated MMNi₅ in the α phase is investigated in detail. Relationship between the amount of hydrogen absorption and time, pressure and temperature has been determined under the initial pressure of 10.31～81kPa at 313～393 K. The activation energy of hydrogen absorption has been found to be equal to 5.02 kJ/mol H₂. The rate and amount of hydrogen absorption increase with the increasing of initial hydrogen pressure. By plotting the absorption amount vs. 1g t, a line is formed with 3 different slopes. From the pressure dependence of absorption it is believed that the rate of absorption is mainly limited by the surface process in the α phase. The general rate equation can be expressed as follows:dn/dt=Ke^-E/RT·P₀（1/t）where K is a constant, P₀ is the initial hyprogen pressure, and t is the time of reaction.更多还原