Three-Dimensional Carbon Electrocatalysts for CO2 or CO Reduction

A challenge in the electrochemical CO 2 reduction reaction (CO 2 RR) is the lack of efficient and selective electrocatalysts to valuable chemicals. Hydrocarbons and valuable chemicals from the CO 2 RR have primarily been observed on metallic Cu. Here, 3D carbon electrocatalysts (diporphyrin molecules; i.e., Pacman) have been investigated as potential CO 2 RR electrocatalysts using density functional theory simulations. This work presents a molecular-level engineering strategy for the development of electrocatalysts toward hydrocarbons. The introduction of a second metal center in the diporphyrins on one hand serves as a proton transfer or CO adsorption site, providing the possibility for the formation of C–H and C–C bonds. On the other hand, the second metal center selectively stabilizes key intermediates like *CH 2 O, *OCH 3, and *OCCHOH, leading to CH 4 and C 2 species production. It has been found that Pacman (Pac) with Mn or Fe is able to produce CH 4 . Furthermore, Pac-CoNi, Pac-CoCu, and Pac-CoCo with pyridine coordination catalysts generate CH 3 OH, while Pac-CoCo might enable C–C coupling, forming C 2 species.