Computational Design of Transition‐Metal‐Doped C ₂ O Monolayers for Efficient and High‐Capacity Hydrogen Storage

The present work demonstrates the impressive H ₂ storage performance of the experimentally synthesized C ₂ O monolayer decorated with selected transition metals (TMs), namely Sc, Ti, and V. The transition metals are strongly adsorbed on C ₂ O, with all three, Sc, Ti, and V, exhibiting robust and stable anchoring. Ab initio molecular dynamics simulations confirm the structural stability of the TM‐doped C ₂ O systems up to 600 K, while their dynamical stability is verified through phonon calculations. Furthermore, nudged elastic band calculations reveal substantial energy barriers for metal migration (Sc = 2.47 eV, Ti = 2.48 eV, and V = 2.37 eV), indicating the absence of metal aggregation and clustering effects. Electronic structure calculations reveal that pristine C ₂ O is semiconducting (2.06 eV), whereas TM incorporation induces metallic behavior with enhanced conductivity. The TM‐decorated C ₂ O monolayer efficiently adsorbs up to five H ₂ molecules per metal site through synergistic electrostatic and van der Waals interactions. Remarkably, the Sc‐, Ti‐, and V‐decorated C ₂ O monolayers deliver theoretical gravimetric hydrogen storage capacities of 8.69, 8.47, and 6.72 wt%, respectively, all exceeding the 5.50 wt% benchmark set by the US Department of Energy (DOE) for 2025. At full hydrogenation, the average H ₂ adsorption energies are calculated to be −0.26, −0.47, and −0.21 eV per H ₂ molecule for Sc‐, Ti‐, and V‐doped C ₂ O systems, respectively. Storage properties under fuel‐cell operating conditions are evaluated in terms of H ₂ uptake and occupation number using the canonical partition function. The corresponding desorption temperature analysis further confirms the reversibility and practical viability of hydrogen storage in these systems.