Solid-solution MAX phase TiVAlC assisted with impurity for enhancing hydrogen storage performance of magnesium...

Area of Science:

• Materials Science
• Chemistry
• Energy Storage

Background:

• Traditional MXene catalysts for magnesium hydride (MgH2) hydrogen storage involve hazardous etching and remove active components.
• Limitations exist in current methods for enhancing MgH2 hydrogen storage, necessitating safer and more effective catalytic approaches.

Purpose of the Study:

• To introduce a solid-solution MAX phase TiVAlC catalyst directly into the MgH2 system to improve hydrogen storage performance.
• To investigate the catalytic mechanism and the influence of impurity phases on the performance of MAX phase catalysts.

Main Methods:

• Directly incorporating solid-solution MAX phase TiVAlC into MgH2 without etching.
• Evaluating hydrogen storage capacity, kinetics, and cyclic stability through isothermal absorption/desorption tests.
• Analyzing catalytic activity through electron transfer mechanisms at interfaces.

Main Results:

• MgH2-10 wt% TiVAlC achieved 6.00 wt% hydrogen release at 300°C (378 s) and 4.82 wt% uptake at 175°C (900 s).
• Excellent cyclic stability with 99.6% capacity retention after 50 cycles was observed.
• Abundant electron transfer at TiVAlC/MgH2 and Ti3AlC2/TiVAlC interfaces enhances catalytic activity.

Conclusions:

• Solid-solution MAX phase TiVAlC is an effective, non-etched catalyst for improving MgH2 hydrogen storage.
• The study highlights the significant role of impurity phases in MAX materials for catalytic enhancement.
• This provides a novel strategy for designing composite catalysts for advanced hydrogen storage materials.