The distribution and flow of water in a CO2 electrolyzer can be defined at variable operating conditions using a 3D model coupled with an analytical electrolyzer.

Gas-fed CO2 electrochemical flow reactors are appealing platforms for the electrolytic conversion of CO2 into fuels and chemical feedstocks at commercially relevant current densities (≥100 mA/cm2). An inherent challenge in the development of these reactors is delivering sufficient water to the cathode to sustain the CO2 reduction reaction, while also preventing accumulation of excess water at the porous cathode (i.e., flooding). We present herein experimental evidence showing cathode flooding in a zero-gap electrolyzer at 200 mA/cm2. This flooding causes a 37% decrease in partial current density for CO production (j CO) along with a 450 mV increase in cell voltage (E cell). We show that the detrimental effects associated with this flooding can be mitigated by pairing thin membranes (i.e., ≤40 μm) with hydrophobic cathodes to enable CO2 electrolysis at commercially relevant conditions (j CO ≥ 100 mA/cm2 and E cell < 3 V).

Bicarbonate electrolysers convert carbon capture solutions into chemicals and fuels and bypass the need for energy-intensive CO2 recovery. Porous metal electrodes are more effective than composite carbon electrodes for this type of electrolyser.

Electroplated 3D printed flow field plates are demonstrated for the electrolysis of water to hydrogen fuels.