Grooved electrodes inspired by the chimney effect to boost mass transport for efficient CO2 electrolysis

Electrochemical CO 2 reduction to CO represents a promising avenue for generating value-added chemicals and achieving global carbon neutrality. However, mass transport plays a significant role in the expression of catalytic intrinsic activity which further restricts the selectivity promotions. Herein, we engineered a grooved electrode to enhance mass transport of dissolved CO 2 in the batch cell, inspired by the chimney effect, a phenomenon that drives the diffusion of species from high-concentration to low-concentration regions via the concentration gradient in the vertical direction. This structure enhances the diffusion depth of reactants within the catalyst layer by increasing the vertical concentration gradient, thereby effectively reducing CO 2 dead zones in the electrode. Through multiphysics modeling, we optimized groove geometry, creating a special grooved electrode that that further reduces CO 2 dead zones. Comparative analysis revealed that increasing the catalyst loading to 20% resulted in CO Faradaic Efficiency improvements of 26% for parallel-grooved electrodes, and 50% for special-grooved electrodes, significantly improving CO conversion in H-cell reactors. And in flow cell tests, the special-grooved electrode maintained a FE CO of 81% at a current density of 150 mA cm −2 , outperforming the other two electrodes.