Reversible hydrogen storage via Ca-decorated T-C₃N monolayer: insights from first-principles calculations

Area of Science:

• Materials Science
• Chemistry
• Physics

Background:

• Two-dimensional carbon-based materials are explored for solid-state hydrogen storage.
• Efficient and reversible hydrogen storage is crucial for clean energy applications.

Purpose of the Study:

• To investigate the hydrogen storage performance of T-C3N monolayer functionalized with calcium atoms.
• To assess the material's stability, capacity, and adsorption mechanism.

Main Methods:

• First-principles calculations were employed.
• Ab initio molecular dynamics (AIMD) simulations were used for stability analysis.
• Spin-polarized band structure, Bader charge analysis, charge density difference (CDD), and projected density of states (PDOS) were utilized.

Main Results:

• Calcium functionalization on T-C3N showed high binding energy and thermal stability.
• The Ca@T-C3N system demonstrated a gravimetric hydrogen storage capacity of 9.15 wt%, exceeding the DOE target.
• Optimal hydrogen adsorption energy (-0.12 to -0.20 eV per H2) and reversibility were confirmed.

Conclusions:

• Ca@T-C3N is a highly efficient and reversible hydrogen storage material.
• The findings provide theoretical insights for experimental exploration of calcium-decorated T-C3N monolayers for fuel cell vehicles.