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-C3N4) 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 H2 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.