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采用NaH和Al为合成原料,镨、钕氢化物为催化剂,通过机械球磨(NaH/Al+6%(摩尔分数)RE-H)(RE=Pr,Nd)复合物的方法并加氢合成NaAlH4络合氢化物,系统研究了催化剂对其吸放氢性能的影响。结果表明,加入PrH2.92和NdH2.27能明显改善NaH/Al复合物的吸放氢动力学性能,有效降低NaAlH4的脱氢温度。(NaH/Al+6%PrH2.92)和(NaH/Al+6%NdH2.27)复合物的120℃吸氢容量分别为3.57%和3.61%(质量分数),170℃放氢容量分别为2.57%和2.95%;且两者均具有较好的吸放氢循环稳定性,但吸(放)氢后样品中均存在少量Na3AlH6相,表明样品的吸(放)氢反应进行得并不彻底,使得其实际吸放氢容量低于理论可逆储氢容量。研究表明,PrH2.92和NdH2.27在球磨、吸/放氢过程中始终稳态存在,起着催化储氢作用;(NaH/Al+6%PrH2.92)复合物的放氢活化能稍低于(NaH/Al+6%NdH2.27)复合物。
Using NaH and Al as raw materials, praseodymium and neodymium hydride as catalysts, the catalyst was prepared by mechanical milling (NaH / Al + 6% RE-H) (RE = Pr, Nd) Complex hydride, systematic study of the impact of the catalyst on its hydrogen absorption and desorption properties. The results show that the addition of PrH2.92 and NdH2.27 can obviously improve the kinetics of hydrogen absorption / desorption of NaH / Al complex and decrease the dehydration temperature of NaAlH4. The hydrogen storage capacities of (NaH / Al + 6% PrH2.92) and (NaH / Al + 6% NdH2.27) complexes were 3.57% and 3.61%, respectively. The hydrogen storage capacities at 170 ℃ were 2.57% and 2.95%, respectively. Both of them have good cyclic stability for hydrogen absorption and desorption. However, a small amount of Na3AlH6 phase is present in the sample after the hydrogen absorption and desorption, indicating that the hydrogen absorption reaction is not complete , Making its actual hydrogen absorption capacity is lower than the theoretical reversible hydrogen storage capacity. The results show that PrH2.92 and NdH2.27 are steady state during ball milling and absorption / desorption, which play a catalytic role in hydrogen storage. The hydrogen evolution activation energy of (NaH / Al + 6% PrH2.92) Below (NaH / Al + 6% NdH2.27) complex.