Metal-Organic Frameworks as an Enzyme-Inspired Heterogeneous Platform for Electrocatalytic CO₂ Reduction

In a world that is running out of natural resources, there is a growing need to design and develop sustainable and green energy resources. In that respect, electrochemically driven reduction of CO₂ to form liquid alternative fuels holds the potential to provide a route for future carbon neutral energy economy. Nevertheless, the slow kinetics of this catalytic reaction demands the development of efficient catalysts in order to drive it at lower overpotentials. Indeed, a variety of molecular catalysts based on metal complexes are capable of electrochemically reducing CO₂. Yet, despite the significant progress in this field, practical realization of molecular catalysts will have to involve a simple and robust way to assemble high concentration of these catalysts in an ordered, reactant-accessible fashion onto a conductive electrode. Our group utilizes Metal-Organic Frameworks (MOFs) as a platform for heterogenizing CO₂ reduction molecular catalysts. Their unique properties (porosity and flexible chemical functionality), enables us to use MOFs for integrating all the different functional elements needed for efficient catalysts: 1) immobilization of molecular catalysts, 2) electron transport elements, 3) mass transport channels, and 4) modulation of catalyst secondary environment. Thus, in essence, MOFs could possess all of the functional ingredients of a catalytic enzyme. In this talk, I will present our recent proof-of-principle study on electrocatalytic CO₂ reduction activity of MOFs incorporating molecular catalysts such as Fe-tetraphenylporphyrin and Mn(bpy)(CO)₃Br.