Bubble Management via Synergy of Dual-Gradient Electrodes and Electrolytes for High-Efficiency Water Electrolysis

Efficient management of bubble behavior on electrode surfaces remains a significant challenge in enhancing water electrolysis performance. Drawing inspiration from the asymmetric wettability of lotus leaves, the selective gas absorption capability of mangrove respiratory roots, and the directional liquid transport mechanism of cactus spines, a bioinspired electrode integrating both wettability and geometric gradients is developed. This design utilizes the Laplace pressure difference induced by the two gradients to mitigate the pinning effect of the three-phase contact line and drive directional three-dimensional bubble transport, thereby substantially improving the hydrogen evolution reaction performance. The regulation of electrolyte ionic strength works synergistically with the electrode structure design, achieving a reduction in potential by up to 22.47% without external field assistance. High ionic strength reduces the charge transfer resistance and promotes rapid bubble detachment via the enhanced solutal Marangoni effect. The constructed fractal structure electrode achieves a Faraday efficiency of 95.80%, demonstrating excellent stability in the continuous generation, directional transport, and efficient collection of hydrogen bubbles.