Metal-cluster (Be, Sc, Ti) decorated C24 nanocages and their hydrogen storage performance

• Investigated H 2 adsorption on Be/Sc/Ti and their cluster decorated on C 24 nanocage • C 24 Ti and C 24 Ti 2 are more suitable for hydrogen storage at ambient conditions • Some of the metal cluster decorated C 24 gets distorted after H 2 adsorption • Be/Sc/Ti metal cluster decorated C 24 nanocages are thermodynamically stable Single Be, Sc, Ti metal atom and their cluster (dimer and trimer) decorated C 24 nanocages are considered for hydrogen storage. A comparison of single metal atom, dimer, and trimer decorated C 24 nanocages and their hydrogen storage performance is carried out. Decoration of single Be atom on C 24 nanocage distorts the nanocage and it is not suitable for hydrogen storage. Be 2 , Be 3 , Sc, Sc 2 , Sc 3 , Ti, Ti 2 , and Ti 3 metal atom/cluster decoration do not distort the C 24 nanocage geometry before H 2 adsorption. After H 2 adsorption Sc 2 , Sc 3 and Ti 3 clusters get broken into their constituent atoms and do not remain in cluster form. Among the metal cluster decorated C 24 structures considered, C 24 Ti and C 24 Ti 2 show thermodynamically favorable H 2 adsorption at ambient conditions without distorting the metal cluster after H 2 adsorption and thus they are more suitable for hydrogen storage at ambient conditions than the other structures considered. Though the Sc 3 and Ti 3 cluster decorated C 24 nanocages show the highest and second highest H 2 uptake capacity among all the structures considered and also thermodynamically favorable H 2 adsorption at ambient conditions, the Sc 3 and Ti 3 clusters get broken after maximum H 2 molecules adsorption.