Lithium and phosphorus-functionalized graphitic carbon nitride monolayer for efficient hydrogen storage: A DFT study

We have explored the consequence of lithium and phosphorous functionalization on the graphitic carbon nitride (g-C₃N₄) monolayer for hydrogen storage using density functional theory. Both pristine and Li and P decorated g-C₃N₄ show a semiconductor nature. The substantial overlap between the s orbital of Li and the p orbital of nitrogen near the Fermi level shows the binding between Li and the g-C₃N₄. The repositioning of HOMO and LUMO is noticed in the Li and P decorated g-C₃N₄. The Bader charge analysis indicates the charge allocation from the Li and P atom to the g-C₃N₄, which results in the adsorption of H₂ by electrostatic interaction. The hydrogen storage capacity of 5.78 wt% is obtained after functionalizing Li and P into the g-C₃N₄. The obtained adsorption energies for the H₂ adsorption and the H₂ desorption temperature confirm that Li and P functionalized g-C₃N₄ is a fascinating candidate for the reversible loading of H₂ at ambient conditions.