Proper NCoordination improves catalytic activity of graphene edge anchored Pt single atom for conversion of methane and carbon dioxide to acetic acid

Abstract

The reaction of directly converting CH₄ and CO₂ into acetic acid has a wide and important application in the chemical industry. In this work, we carried out systematically computational chemistry study on the catalytic performance of the single Pt atom catalyst anchored at the edge of N-doped graphene for the direct co-conversion of CH₄ and CO₂ to acetic acid based on density functional theory (DFT) calculations. The DFT calculation results show the catalytic activity of single Pt atom is significantly tuned by the local N-atom coordination. The Pt-N₁C exhibits the best catalytic performance of CH₄ and CO₂ conversion with a low rate-determining free energy barrier of 0.69 eV The microkinetic modeling shows that the TOF of CH₃COOH on Pt-N₁C catalyst reaches 7.63×10² s⁻¹ at 600 K and 2 bar Further analysis shows that the adsorption strength of reactant CH₄ and CO₂ is linearly correlated with the energy level of d_xy orbital center of Pt atom. A moderate adsorption strength of CH₄ and CO₂ over the Pt-N₁C leads to easier activation of methane and migration of H and CH₃ during the conversion reaction.