Tailoring the capability of carbon nitride (C ₃ N) nanosheets toward hydrogen storage upon light transition metal decoration

To nurture the full potential of hydrogen (H 2 ) as a clean energy carrier, its efficient storage under ambient conditions is of great importance. Owing to the potential of material-based H 2 storage as a promising option, we have employed here first principles density functional theory calculations to study the H 2 storage properties of recently synthesized C 3 N monolayers. Despite possessing fascinating structural and mechanical properties C 3 N monolayers weakly bind H 2 molecules. However, our van der Waals corrected simulations revealed that the binding properties of H 2 on C 3 N could be enhanced considerably by suitable Sc and Ti doping. The stabilities of Sc and Ti dopants on a C 3 N surface has been verified by means of reaction barrier calculations and ab initio molecular dynamics simulations. Upon doping with C 3 N, the existence of partial positive charges on both Sc and Ti causes multiple H 2 molecules to bind to the dopants through electrostatic interactions with adsorption energies that are within an ideal range. A drastically high H 2 storage capacity of 9.0 wt% could be achieved with two-sided Sc/Ti doping that ensures the promise of C 3 N as a high-capacity H 2 storage material.