Hydrogen molecule adsorption on heptazine and triazine carbon nitride nanosheets and their selected-elements (periods 3 and 4)-decorated derivatives as hydrogen storage materials

The hydrogen adsorption on heptazine-based graphitic carbon nitride nanosheets (hg-C3N4-NSs) and triazinebased graphitic carbon nitride nanosheets (tg-C3N4-NSs) and their derivatives, which were decorated with selected elements from period 3 (Al, Si, P, and S) and period 4 (Ga, Ge, As, and Se), was investigated using the periodic-DFT method at the PBEPBE/6-31G(d) level of theory. The results reveal that the band gaps of all decoration atoms and H2 adsorbed on element -decorated hg-C3N4-NSs and tg-C3N4-NSs are lower than those of the pristine material. Notably, P -decorated hg-C3N4-NS and tg-C3N4-NS exhibit the strongest chemical adsorption, with adsorption energies of -1.73 eV and - 1.51 eV, respectively, indicating their significant potential for application as hydrogen storage materials. Furthermore, the Ga-decorated hg-C3N4-NS and tg-C3N4-NS as hydrogen gas sensing materials are suggested.