PtおよびNiドープグラフェン上におけるCO₂水素化の触媒機構：DFT比較研究
To address the environmental burden of CO₂ as a greenhouse gas, density functional theory (DFT) calculations using the M06-2X functional were applied to examine CO₂ hydrogenation by H₂ over Pt- and Ni-doped graphene surfaces. Two mechanistic pathways were evaluated. In the bimolecular pathway, co-adsorption of CO₂ and H₂ is followed by hydrogen atom transfer to form an OCOH intermediate, which subsequently yields formic acid via C–H bond formation. In the termolecular pathway, H₂ is activated directly by two pre-adsorbed CO₂ molecules, with formic acid formation identified as the rate-determining step. Activation energies for OCOH intermediate formation were 20.8 kcal/mol on Pt-doped and 47.9 kcal/mol on Ni-doped graphene. For the termolecular route, rate-determining step barriers were 28.8 and 45.5 kcal/mol, respectively. These results indicate that Pt-doped graphene exhibits substantially greater catalytic efficiency than its Ni-doped counterpart for CO₂ reduction to value-added products.
Pt-doped graphene lowers the activation energy for OCOH intermediate formation to 20.8 kcal/mol compared with 47.9 kcal/mol on Ni-doped graphene, facilitating CO₂ hydrogenation to formic acid via both bimolecular and termolecular pathways.
This is basic research at the cellular or molecular level. For human application, inhalation is the most promising delivery route, but inhalation carries explosion risk and concentration matters (empirical LFL of 10%; high-concentration devices are not recommended).
See also:
https://h2-papers.org/en/papers/28858642