Tailoring the absorption–desorption properties of KSiH3 compound using nano-metals (Ni, Co, Nb) as catalyst

• The structural properties of catalyst modified KSi system are presented.
• The sorption kinetics is shown to be improved by catalyst doping.
• Nano-Ni doping reduce the sorption activation energy from 142 to 106 kJ mol−1.

Recently KSiH3 has been proposed as an attractive contender toward hydrogen storage media, owing to its high storage capacity i.e. 4.3 wt% within a good P-T window. The high activation energy for desorption allows KSiH3 to desorb hydrogen slowly only at 200 °C in more than 5 h. Moreover, the efforts to improve the kinetics by means of milling with carbon powder disproportionate KSiH3 into KH, Si and K–Si intermetallic phases. A number of known nano-metals viz. Ni, Co, and Nb are attempted in order to improve the sorption properties of KSiH3. Nano-Ni is found to be most effective catalyst with the lowest value of activation energy 106 kJ mol−1 in comparison to 142 kJ mol−1 for as annealed KSi sample.