Mitigating Bubble Traffic in Gas-Evolving Electrodes via Spinodally Derived Architectures

Porous electrodes are widely used in the industry because of their high surface area to volume ratio. However, the stochastic morphology of most commercially available porous electrodes results in poor electrical connections in the solid phase and inefficient mass transport through the pore phase. This can be especially detrimental for gas-evolving processes such as water electrolysis for hydrogen and oxygen generation. Bicontinuous interfacially jammed emulsion gels (bijels) offer templates from which to create porous electrodes with robust solid-state interconnectivity and a uniform pore structure that facilitate improved electron and mass transport. In this study, gas release rates and electrochemical experiments are utilized to study the effects of powder- and bijel-derived microstructures on hydrogen generation by water electrolysis. The bijel-derived electrodes are shown to expel product gas faster and require up to 25% less overpotential to drive water electrolysis over the range of current densities tested (-5 to -40 mA/cm²) than their powder-derived analogs. Our findings suggest that the uniform and bicontinuous domains of bijel-derived porous electrodes can mitigate the limited current distribution and deleterious bubble effect found in stochastic electrodes, in turn improving the overall performance of electrolytic processes requiring transport of gaseous species.