Direct Electrochemical Conversion of CO₂ Sorbent Solution to Formate by a Molecular Iron Catalyst

High Resolution Image Download MS PowerPoint Slide The reactive capture of CO 2 (RCC) is the direct conversion of CO 2 to a product that is performed in a sorbent where CO 2 has been captured and stored. Here, we report that the molecular cluster electrocatalyst [Fe 4 N(CO) 12 ] − ( 1 – ) can be used for RCC to produce formate with 89% faradaic efficiency. In this integrated process, a solution of monoethanolamine (MEA) and water in a ratio of 30:70 with added 0.1 M KHCO 3 serves a dual purpose as the CO 2 capture sorbent and the reaction solution for the electrochemical reduction of CO 2 . Under 1 atm of CO 2, this reaction solution is buffered at pH = 7.9 as HCO 3 – /CO 3 2–, and the CO 2 loading is 2.67 M. Mechanistic studies performed using cyclic voltammetry indicate that the CO 2 dissolved in solution serves as the substrate. Mechanistic insights into heterogeneous RCC processes are also discussed.