XPS Investigation on Improving Hydrogen Sorption Kinetics of the KSiH₃ System by Using Zr-Based Catalysts

Area of Science:

• Materials Science
• Hydrogen Storage
• Catalysis

Background:

• The KSiH3 system exhibits excellent theoretical hydrogen storage capacity (4.3 wt%).
• High activation energy hinders reversible hydrogen absorption/desorption at practical temperatures, despite favorable thermodynamics.
• Existing catalysts have been explored to improve the kinetics of the KSiH3 system.

Purpose of the Study:

• To investigate the use of Zirconium (Zr)-based catalysts to reduce the activation energy of the KSi/KSiH3 system.
• To identify the most effective Zr-based catalyst for enhancing hydrogen storage kinetics.

Main Methods:

• Theoretical evaluation of KSiH3 system for hydrogen storage.
• Experimental testing of various Zr-based catalysts, including ZrH2, to lower activation energy.
• Investigation of the catalytic mechanism using X-ray photoelectron spectroscopy (XPS).

Main Results:

• The addition of Zirconium hydride (ZrH2) to the KSiH3 system resulted in the lowest observed activation energy of 87 kJ mol-1.
• This reduction in activation energy is crucial for enabling reversible hydrogen storage at practical temperatures.
• XPS analysis provided insights into the mechanism behind the catalytic improvement.

Conclusions:

• ZrH2 is an effective catalyst for the KSiH3 system, significantly reducing the activation energy for hydrogen storage.
• The findings suggest that catalyzed KSiH3 systems hold potential for practical hydrogen storage applications.
• Further research into the catalytic mechanism can optimize material performance.