Abstract：
Overall water splitting is a promising technology for sustainable hydrogen production, but the primary challenge is removing bubbles from the electrode surface quickly to increase hydrogen production. Inspired by the directional fluid transport properties of natural biological surfaces like Nepenthes peristome and Morpho butterfly\'s wings, here a strategy is demonstrated to achieve highly efficient overall water splitting by a bubble-guidance electrode, that is, an anisotropic groove-micro/nanostructured porous electrode (GMPE). Gradient groove micro/nanostructures on the GMPE serve as high-speed bubble transmission channels and exhibit superior bubble-guidance capabilities. The synergistic effect of the asymmetric Laplace pressure generated between microscale porous structure and groove patterns and the buoyancy along the groove patterns pushes the produced bubbles directionally to spread, transport, and detach from the electrode surface in time. Moreover, the low adhesive nanosheet arrays are beneficial to reduce bubble size and increase bubble release frequency, which cooperatively improve mass transfer with the microscale structure. Notably, GMPE outperforms planar-micro/nanostructured porous electrode (PMPE) in hydrogen/oxygen evolution reactions, with GMPE||GMPE showing better water splitting performance than commercially available RuO2||20 wt.% Pt/C. This work improves electrodes for better mass transfer and kinetics in electrochemical reactions at solid-liquid-gas interfaces, offering insight for designing and preparing gas-involved photoelectrochemical electrodes.
摘要：
整体水分解是可持续制氢的有前途的技术，但主要的挑战是从电极表面迅速去除气泡，以增加氢气产量。受天然生物表面的定向流体传输特性的启发，如猪笼草和Morpho蝴蝶的翅膀，在这里证明了一种策略，通过气泡引导电极实现高效的整体水分解，也就是说,各向异性凹槽微/纳米结构多孔电极(GMPE)。GMPE上的梯度凹槽微/纳米结构用作高速气泡传输通道，并具有出色的气泡引导能力。微尺度多孔结构和凹槽图案之间产生的不对称拉普拉斯压力和沿着凹槽图案的浮力的协同效应推动产生的气泡定向扩散，运输,并及时从电极表面脱离。此外，低粘性纳米片阵列有利于减小气泡尺寸和增加气泡释放频率,与微尺度结构协同改善传质。值得注意的是,GMPE在氢/氧析出反应中优于平面微/纳米结构多孔电极（PMPE），GMPE||GMPE显示出比市售RuO2||20wt.%Pt/C。这项工作改善了电极在固-液-气界面的电化学反应中更好的传质和动力学，为设计和制备涉及气体的光电化学电极提供见解。
