XPS Investigation on Improving Hydrogen Sorption Kinetics of the KSiH 3 System by Using Zr-Based Catalysts.

The superior hydrogen storage properties makes the KSiH 3 system a potential hydrogen storage material for practical applications. A theoretical capacity of 4.3 wt% bring this material to the front line of all the available hydrogen storage materials; however, the activation barrier of the reaction restricts the system to absorb and desorb hydrogen reversibly at elevated temperatures even if the thermodynamics suggest its room temperature operation. Several catalysts have already been tested to enhance its kinetic properties. In this work, the efforts were made to reduce the activation energy by using Zr-based catalysts to the KSi/KSiH 3 system. The value of activation energy was found to be lowest (i.e., 87 kJ mol -1) for the ZrH 2 -added KSiH 3 system. The mechanism of this improvement was investigated by using X-ray photoelectron spectroscopy (XPS).