Tailoring the capability of carbon nitride (C₃N) nanosheets toward hydrogen storage upon light transition metal...

To nurture the full potential of hydrogen (H₂) as a clean energy carrier, its efficient storage under ambient conditions is of great importance. Owing to the potential of material-based H₂ storage as a promising option, we have employed here first principles density functional theory calculations to study the H₂ storage properties of recently synthesized C₃N monolayers. Despite possessing fascinating structural and mechanical properties C₃N monolayers weakly bind H₂ molecules. However, our van der Waals corrected simulations revealed that the binding properties of H₂ on C₃N could be enhanced considerably by suitable Sc and Ti doping. The stabilities of Sc and Ti dopants on a C₃N surface has been verified by means of reaction barrier calculations and ab initio molecular dynamics simulations. Upon doping with C₃N, the existence of partial positive charges on both Sc and Ti causes multiple H₂ molecules to bind to the dopants through electrostatic interactions with adsorption energies that are within an ideal range. A drastically high H₂ storage capacity of 9.0 wt% could be achieved with two-sided Sc/Ti doping that ensures the promise of C₃N as a high-capacity H₂ storage material.