Electrochemical CO₂ Reduction in a Continuous Non-Aqueous Flow Cell with [Ni(cyclam)]²

A significant number of molecular catalysts have been developed for electrochemical CO₂ reduction with high efficiency and selectivity; however, testing of these electrocatalysts in an application-ready system is lacking. Here, we present an example of a nonaqueous flow cell electrolyzer with [Ni(cyclam)]²⁺ as the homogeneous electrocatalyst for CO₂ reduction. Using ferrocene as a sacrificial electron donor and ammonium salts as both electrolyte and proton donor, efficient catalytic CO₂ reduction is achieved. The nonaqueous design shows high selectivity for the reduction of CO₂ to CO (>80%) and achieves high current densities with a graphite felt working electrode (up to 50 mA·cm^-2 with 0.5 M proton donor in MeCN solution), producing >40 mL·h^-1 of CO. The choice of a molecular electrocatalyst, solvent, and proton donor are the key factors for achieving high activity with an efficient flow electrolyzer and the eventual development of a viable continuous process.