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Electrolysis of Gaseous CO 2 to CO in a Flow Cell with a Bipolar Membrane

2017; American Chemical Society; Volume: 3; Issue: 1 Linguagem: Inglês

10.1021/acsenergylett.7b01017

2380-8195

Danielle A. Salvatore, David M. Weekes, Jingfu He, Kevan E. Dettelbach, Yuguang Li, Thomas E. Mallouk, Curtis P. Berlinguette,

Advanced battery technologies research

The conversion of CO2 to CO is demonstrated in an electrolyzer flow cell containing a bipolar membrane at current densities of 200 mA/cm2 with a Faradaic efficiency of 50%. Electrolysis was carried out by delivering gaseous CO2 at the cathode with a silver catalyst integrated in a carbon-based gas diffusion layer. Nonprecious nickel foam in a strongly alkaline electrolyte (1 M NaOH) was used to mediate the anode reaction. While a configuration where the anode and cathode were separated by only a bipolar membrane was found to be unfavorable for robust CO2 reduction, a modified configuration with a solid-supported aqueous layer inserted between the silver-based catalyst layer and the bipolar membrane enhanced the cathode selectivity for CO2 reduction to CO. We report higher current densities (200 mA/cm2) than previously reported for gas-phase CO2 to CO electrolysis and demonstrate the dependence of long-term stability on adequate hydration of the CO2 inlet stream.