Enhancement in hydrogenation dehydrogenation kinetics of KSiH3 by the addition of Ti-based catalysts

Abstract

Recently, KSiH3 system has emerged as potential hydrogen storage alloy system due to its appropriate thermodynamic parameters and almost double reversible gravimetric hydrogen content as compared to most of the BCC alloys. The hydrogenation enthalpy value of 28 kJ mol−1 H2 propose its operation at room temperature, however, it could be operated only above 100 °C with a hydrogen storage capacity of 4.3 wt% as evidenced from experiments, due to high activation energy. The present work is designed to reduce the activation energy and investigate the effect of Ti-based catalysts i.e. Ti, TiO, Ti2O3, TiO2, TiCl3, TiF4 and TiH2 on hydrogenation properties of KSiH3 system. The results suggested the superiority of TiO over other catalysts with the reduction of activation energy to 82 kJ/mol H2 from the 130 kJ/mol H2 for the 1 h milled sample without catalyst.

Keywords

• Hydrogen storage
• Silanide
• Ball milling
• Catalyst
• Activation energy