Investigating the interplay between charge transfer and CO 2 insertion in the adsorption of a NiFe catalyst for CO 2 electroreduction on a graphite support through DFT computational approaches.

This article describes a density functional theory (DFT) study to explore a bio-inspired NiFe complex known for its experimental activity in electro-reducing CO 2 to CH 4 when adsorbed on graphite. The coordination properties of the complex are investigated in isolated form and when physisorbed on a graphene surface. A comparative analysis of DFT approaches for surface modeling is conducted, utilizing either a finite graphene flake or a periodic carbon surface. Results reveal that the finite model effectively preserves all crucial properties. By examining predicted structures arising from CO 2 insertion within the mono-reduced NiFe species, whether isolated or adsorbed on the graphene flake, a potential species for subsequent electro-reduction steps is proposed. Notably, the DFT study highlights two positive effects of complex adsorption: facile electron transfers between graphene and the complex, finely regulated by the complex state, and a lowering of the thermodynamic demand for CO 2 insertion.