Molecular engineering of metalloporphyrins and phthalocyanines for homogeneous and heterogeneous CO₂ electroreduction

This review provides an overview of recent advances in CO₂ electrocatalysis, starting with the development of homogeneous electrocatalytic systems. We focused on porphyrin and phthalocyanine based molecular catalysts where different chemical strategies have been implemented drawing inspiration from natural enzyme systems that process CO₂, such as hydrogen bonding, proton relay, bimetallic cooperative action, electrostatic interactions and structural dynamics to help enhancing the selectivity and efficiency of electrochemical CO₂ reduction. The discussion then expands to heterogeneous processes in traditional H-cells, and more relevant flow-cell setups integrated with gas diffusion electrodes. A special focus is given to the growing trend of hybrid molecular-metallic co-catalyst systems, which are driving significant progress in heterogeneous CO₂ electrocatalysis.