Lithium-doped triazine-based graphitic C₃N₄ sheet for hydrogen storage at ambient temperature

Due to its porous structure and light mass the recently synthesized triazine-based graphitic C₃N₄ (g-C₃N ₄) sheet is a promising material for gas storage. First-principles calculations based on density functional theory were used to study the hydrogen storage capacity of Li doped g-C₃N₄ under ambient thermodynamic conditions. The most stable binding site of Li atom on it is the open-hollow site with a binding energy of 3.26 eV. Based on the force field parameters derived from quantum chemistry calculations, we have further performed grand canonical Monte Carlo (GCMC) simulations to investigate H ₂ adsorption isotherms on g-C₃N₄ sheet. We find that the adsorption energy of H₂ is 3.48 kcal/mol, and the excess uptake of hydrogen is about 4.50 wt% at 298 K and 100 bar, showing potential as a hydrogen storage material.