(478j) Comparative Analysis of Biomimetic CO2 Hydration over Computationally Designed Ruthenium Cluster Decorated Graphene/Carbon Nanotube

Ruthenium cluster decorated graphene (Ru/Gr) and carbon nanotube (Ru/CNT) were optimized to observe the catalytic activity of CO₂ hydration reaction over the proposed catalysts using density functional theory calculations. Ru/Gr and Ru/CNT were found to be active for biomimetic CO₂ hydration reaction. CO₂ hydration mechanism over Ru/Gr and Ru/CNT followed the CO₂ hydration mechanism catalyzed by α-carbonic anhydrase enzyme. For CO₂ to HCO₃^- ion conversion, four elementary steps were observed as OH^- ion formation with H₂O dissociation, CO₂ bending in presence of OH^- ion, HCO₃^- ion formation by proton migration and HCO₃^- ion desorption with H₂O addition. HCO₃^- ion formation step was found to be the rate limiting step. Potential energy surfaces were developed for the reaction. Activation barrier of H₂O dissociation was observed lesser over Ru/CNT than Ru-Gr. Ru/CNT was found to be more active than Ru/Gr.