Bionic stacked 3D engineered functional electrodes for ultra-high efficient hydrogen production

Abstract The bubbles formed on the electrodes tend to stick to the reaction area during hydrogen (H 2 ) production, hindering the continuous reaction, which drastically reduces the H 2 production efficiency. In this work, a customizable multifunctional three-dimensional (3D) electrode with bionic structures is proposed and precisely fabricated by the projection microstereolithography (PμSL) 3D printing technique, which facilitates the catalytic reaction and the detachment of H 2 bubbles with an asymmetrically wetted bioinspired functional membrane to allow bubbles to pass through based on Janus effects. The 3D bionic functional electrodes exhibit excellent H 2 production performance. At the same voltage, the current density of our 3D electrode is 2.5 times greater than that of a two-dimensional (2D) electrode and 8 times greater than that of a one-dimensional (1D) common flat electrode with the same surface area. Moreover, the amount of H 2 collected from a 3D bionic functional electrode is 53.9% and 172.1% greater than that collected from 2D and 1D electrodes with the same catalyst size, respectively. Significantly, a 400 cm 2 panel reactor system based on biomimetic 3D functional electrodes enables one-week continuous operation with ultra-high safety and durability in H 2 production. Coupled with a solar panel, it achieves long-term outdoor H 2 production and gas collection.