Realization of heterogeneous electrochemical CO2-to-fuel conversion via molecular catalysis under high-flux conditions requires the assembly of large quantities of reactant-accessible catalysts on conductive surfaces. As a proof of principle, we demonstrate that electrophoretic deposition of thin films of an appropriately chosen metal-organic framework (MOF) material is an effective method for immobilizing the needed quantity of catalyst. For electrocatalytic CO2 reduction, we used a material that contains functionalized Fe-porphyrins as catalytically competent, redox-conductive linkers. The approach yields a high effective surface coverage of electrochemically addressable catalytic sites (∼1015 sites/cm2). The chemical products of the reduction, obtained with ∼100% Faradaic efficiency, are mixtures of CO and H2. These results validate the strategy of using MOF chemistry to obtain porous, electrode-immobilized, networks of molecular catalysts having competency for energy-relevant electrochemical reactions.
- CO reduction
- metal organic frameworks
- redox conductivity
- solar fuel
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