Enhanced bicarbonate electrolysis using bipolar membranes with accelerated water dissociation

Bicarbonate electrolysis connects CO₂ capture and electrochemical reduction by directly converting bicarbonate as the captured form of CO₂ into valuable chemicals and fuels, potentially reducing the energy required for CO₂ conversion. This process typically relies on bipolar membranes (BPMs), whose sluggish water dissociation (WD) kinetics unfortunately demand large operating voltages and limit energy efficiency. Here, we demonstrate that integrating suitable WD catalysts within BPMs is key to enabling efficient bicarbonate electrolysis. Graphene oxide (GO) is identified as a low-cost, scalable and highly active WD catalyst. At an optimal mass loading of 10 μg cm^-2, GO-enabled BPM reactors deliver a formate Faradaic efficiency (FE) of 60 ± 1% at 360 mA cm^-2 and 3.87 V in bicarbonate electrolysis - corresponding to an approximately 2 V reduction in cell voltage and nearly twice the formate energy efficiency (EE) compared to commercially available BPMs. Our reactors also achieve at least 2.4-fold higher formate partial current density at comparable cell potentials relative to previous state-of-the-art bicarbonate electrolysis systems. Derived from abundant graphite, this WD catalyst offers a promising pathway to advancing BPM-based technologies for carbon-negative chemical manufacturing as well as other next-generation energy systems.