Electrochemical CO2 reduction by heterogeneous catalysts of 2D metal-organic frameworks comprising metal-coordinated porphyrins

In this study, we employed first-principles computations to design two-dimensional (2D) metal organic framework (MOF) electrocatalysts with metal-porphyrin nanosheets (TM-TCPP-MOF), for CO2 electroreduction. We investigated 3d-transition metal doping on the porphyrin units to screen for efficient catalysts. Structural stability, including thermodynamic and electrochemical stability, was evaluated through binding energy, cohesive energy, formation energy, and dissolution potential analyses. Our results show that TM-TCPP-MOF catalysts are both thermodynamically and electrochemically stable, and the predicted Gibbs free energy profiles indicate HCOOH and CO as the most likely products. The stability of *COOH on Fe-, Co-, Ni-, and Cu-TCPP-MOF leads to CO formation, while *OCHO stabilization on Sc-, Ti-, V-, Cr-, and Mn-TCPP-MOF favors HCOOH production. The competitive hydrogen evolution reaction (HER) was evaluated to study the selectivity. Cr-TCPP-MOF and CoTCPP-MOF exhibit superior selectivity and activity for CO2 electroreduction.