Mimicking Enzymatic Active Site Environment on Heterogeneous Electrodes: A Catalyst-Polymer Hybrid System for Selective CO2 Reduction Reaction in Water

forthcoming

Surging energy needs and fossil fuel reliance have triggered a concerning rise in CO2 emissions, raising the frequency of devastating climate-related disasters. Despite expanding renewable energy sources like solar and wind, their intermittent nature has spurred demand for better storage technologies due to the limitations of current batteries. Heavy industries and transport sectors still rely on fossil-based fuels. Although H2 appears as an alternative, challenges remain regarding its transport. Electrocatalytic CO2 reduction (eCO2R) emerges as a solution, turning CO2 into valuable chemicals and fuels (compatible with existing industrial frameworks) using green electricity. Metal-based heterogeneous eCO2R catalysts exhibit notable stability but they face product selectivity issues, requiring energy-intensive downstream separation methods. Inspired by the active site of [NiFe]-CODH enzyme which efficiently converts CO2 to CO, many 2nd-sphere-modified molecular complexes (MCs) have been developed, showing elevated selectivity, efficiency, and stability. But most of them function within organic media, limiting their integration into devices. Moreover, synthesizing these 2nd sphere-modified MCs is highly resource-intensive. MEASURE-CO2RR aspires to mimic the enzymatic active site on heterogeneous electrodes. This is achieved by encapsulating MCs within commercially available polymers, introducing both the 2nd-sphere (stabilizing intermediates) and tertiary-sphere effects (precise H+ delivery). Aiming to achieve high selectivity, catalytic current, and stability within an aqueous medium, MEASURE-CO2RR stands out by encompassing the development of hybrid catalytic systems, thorough mechanistic studies utilizing in-situ spectroscopic techniques, and eventual integration of these hybrid systems into CO2-electrolyzers. This marks a significant stride towards the essential industrial implementation of eCO2R, effectively aligning with the objectives of the EU Green Deal.