Theoretical Investigation of Ethane‐to‐Aromatics Conversion Over [ GaH 2 ]‐ ZSM ‐5

ABSTRACT Gallium‐modified ZSM‐5 (Ga‐ZSM‐5) zeolites are highly effective catalysts for the ethane‐to‐aromatics (ETA) process. In this work, the catalytic role of the Ga + , [GaO] + and [GaH 2 ] + species in Ga–ZSM‐5 is investigated using a cluster model and density functional theory (DFT) calculations, focusing on ethane dehydrogenation (EDH) and subsequent ethene aromatization steps. Anharmonic vibrational analysis reveals that the H–Ga–H asymmetric stretching vibration corresponds to the experimentally observed band. Moreover, the Interaction Region Indicator (IRI) analysis shows that the ethane‐zeolite interaction is dominated by van der Waals forces. Although ethane activation over [GaH 2 ] + remains energetically demanding during the EDH stage, with an activation free energy of 68.7 kcal mol −1 , the subsequent steps are comparatively more accessible, and the active site can be regenerated without the severe energetic penalty observed for the Ga + and [GaO] + pathways. Finally, C 6 ring closure is identified as the turnover frequency‐determining transition state species for the ETA process. These results provide detailed mechanistic insight into the role of [GaH 2 ] + in the ETA process and support the use of cluster models as reliable and efficient alternatives for investigating metal‐modified zeolite catalysis.