Exploring the catalytic potential of transition metal decorated Al12N12 nanocages as a single atom catalyst for efficient hydrogen adsorption and dissociation reaction.

Hydrogen is a key alternative to fossil fuels and plays a crucial role in industrial hydrogenation. This study employs first-principles density functional theory (DFT) simulations to investigate transition-metal-decorated Al12N12 single-atom catalysts (SACs) for H2 adsorption and dissociation. Interaction energy calculations indicate excellent thermodynamic stability of the catalysts, with Ti@Al12N12 exhibiting the strongest interaction energy of -2.56 eV. Natural bond orbital (NBO) and frontier molecular orbital (FMO) analyses reveal significant electron transfer from TM atoms to Al12N12, and a reduction of the HOMO-LUMO gap from 3.86 eV to 1.72 eV. The Ti@Al12N12 catalyst exhibits the lowest activation barrier, 0.005 eV, for H2 dissociation. Mechanistic insights indicate that atomic hydrogen (2H*) is more stable than molecular H2, with an energy release up to -1.64 eV. Bidirectional IRC calculations validated the H2 dissociation pathways on TM@Al12N12 catalysts. The blue patches in IRI analysis confirm covalent interactions between hydrogen and TM atoms. This study provides insights into designing efficient SACs for hydrogen dissociation.