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The industrialization of the electrochemical reduction of CO2 toward CO in aqueous electrolytes has recently been started using silver‐based gas diffusion electrodes. The performance of a CO2‐to‐CO electrolyzer model on a 10‐cm2 cell size is assessed with respect to operating pressure, achievable current density at faradaic efficiency of CO above 90 %, composition of gas streams and operational lifetime. Operational lifetime has exceeded 1500 h. The first scaling step to 300 cm2 has been accomplished. The rated power of such a cell is around 300 W. [ABSTRACT FROM AUTHOR]

We report on the long-term stability of the electrochemical reduction of CO2 at copper sheet electrodes by continuously applying rectangular, pulsed voltage cycles in series. Each pulse cycle consisted of an anodic and a cathodic voltage level. The parameters of the pulse cycle were systematically modified: cathodic (-1.5...-1.8 V) and anodic voltage levels (-0.88...+0.15 V), and ratio of anodic to cathodic pulse duration (5 s:5 s...5 s:500 s). The electrolysis runs were conducted in a divided H-cell. Volatile reaction products (CO, CH4, C2H4, H2) were analyzed with a gas chromatograph in intervals of 7.3 min. We achieved fairly stable faradaic efficiencies (FE) for hydrocarbon formation in the range of 20 to 35% FE for C2H4 and 20 to 50% FE for CH4 during 16 h of electrolysis and a remarkable suppression of hydrogen evolution reaction (HER) down to 10% FE. Additionally, we show data of two long-term electrolysis runs of 85 h and 95 h duration, respectively. Even for this prolonged electrolysis times, an outstanding, fairly constant suppression of HER and a high efficiency for the formation of carbon containing gaseous products (CO, CH4, C2H4) was achieved. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of CO 2 using Cu-based gas diffusion electrodes opens the way to green chemical production as an alternative to thermocatalytic processes and a storage solution for intermittent renewable electricity. However, diverse challenges, including short lifetimes, currently inhibit their industrial usage. Among well-studied determinants such as catalyst characteristics and electrode architecture, possible effects of byproduct accumulation in the electrolyte as an operational factor have not been elucidated. This work quantifies the influence of ethanol, n -propanol, and formate accumulation on selectivity, stability, and cell potential in a CO 2 -to-C 2 H 4 electrolyzer. Alcohols accelerated flooding by degrading the hydrophobic electrode characteristics, undermining selective and stable ethylene formation. Furthermore, high alcohol concentrations triggered the catalyst layer's abrasion and structural disfigurements in the Nafion 117 membrane, leading to high cell potentials. Therefore, continuous removal of alcohols from the electrolyte medium or substantial modifications in the cell components must be considered to ensure long-term performing CO 2 -to-C 2 H 4 electrolyzers.