CoTCNQ as a catalyst for CO₂ electroreduction: a first-principles r²SCAN meta-GGA investigation

Using first principles calculations we investigate cobalt-coordinated tetracyanoquinodimethane (R-CoTCNQ) as a potential catalyst for the CO₂ electroreduction reaction (CO₂ERR). We determine that exchange–correlation functionals beyond the generalized gradient approximation (GGA) are required to accurately describe the spin properties of R-CoTCNQ, therefore, the meta-GGA r²SCAN functional is used in this study. The free energy CO₂ERR reaction pathways are calculated for the reduced catalyst ([R-CoTCNQ]^−1e) with reaction products HCOOH and HCHO predicted depending on our choice of electrode potential. Calculations are also performed for [R-CoTCNQ]^−1e supported on a H-terminated diamond (1 1 0) surface with reaction pathways being qualitatively similar to the [R-CoTCNQ]^−1e monolayer. The inclusion of boron-doping in the diamond support shows a slightly improved CO₂ERR reaction pathway. Furthermore, structurally, supported R-CoTCNQ provide a high specific area of active Co active sites and could be promising catalysts for future experimental consideration.