(381f) CO2 Conversion in Pressure-Tunable Organic CO2-Expanded Electrolytes

Electrochemical studies of carbon dioxide (CO₂) conversion with both heterogeneous and molecular catalysts are typically carried out i) in aqueous solution and ii) in a narrow range of near-ambient CO₂ pressures where low CO₂ solubilities can limit the rate of catalysis. In this talk, the impacts and opportunities in use of higher liquid-phase concentrations of CO₂ in the context of CO₂ conversion chemistry & electrochemistry will be discussed. We have previously demonstrated that multi-molar CO₂ concentrations can be achieved in polar organic solvents (e.g., acetonitrile, dimethylformamide) containing supporting electrode at relatively mild pressures and ambient temperatures. We have termed these CO₂-rich, electrolyte-containing solutions as CO₂-eXpanded Electrolytes (CXEs) because significant volumetric expansion of the liquid phase accompanies CO₂ dissolution. Insights into the performance of two model catalytic systems, polycrystalline gold and the workhorse molecular catalyst [Re(CO)₃(bpy)Cl] (where bpy is 2,2′-bipyridyl), will be discussed, including analysis of cyclic voltammetry data, quantitative data regarding enhancements in the space-time yield of products, and our latest directions for improving catalysis of CO₂ conversion in CXEs. As pressure-tunable CXEs can significantly intensify CO₂ reduction rates over known electrocatalysts by alleviating substrate starvation, CO₂ pressure and the selection of appropriate solvent appear to be crucial variables for optimization in electrocatalytic CO₂ conversion.