Influence of K2NbF7Catalyst on the Desorption Behavior of LiAlH4

In this study, the modification of the desorption behavior of LiAlH(4)by the addition of K(2)NbF(7)was explored for the first time. The addition of K(2)NbF(7)causes a notable improvement in the desorption behavior of LiAlH4. Upon the addition of 10 wt.% of K2NbF7, the desorption temperature of LiAlH(4)was significantly lowered. The desorption temperature of the LiAlH4+ 10 wt.% K(2)NbF(7)sample was lowered to 90 degrees C (first-stage reaction) and 149 degrees C (second-stage reaction). Enhancement of the desorption kinetics performance with the LiAlH4+ 10 wt.% K(2)NbF(7)sample was substantiated, with the composite sample being able to desorb hydrogen 30 times faster than did pure LiAlH4. Furthermore, with the presence of 10 wt.% K2NbF7, the calculated activation energy values for the first two desorption stages were significantly reduced to 80 and 86 kJ/mol; 24 and 26 kJ/mol lower than the as-milled LiAlH4. After analysis of the X-ray diffraction result, it is believed that thein situformation of NbF4, LiF, and K or K-containing phases that appeared during the heating process promoted the amelioration of the desorption behavior of LiAlH(4)with the addition of K2NbF7.