Light-driven ion (proton) transport is a crucial process both for photosynthesis of green plants and solar energy harvesting of some archaea. Here, we describe that TiO₂/C₃N₄ semiconductor heterojunction nanotube membrane can realize a similar light-driven directional ion transport performance as biological systems. This heterojunction system can be fabricated by two simple deposition steps. Under unilateral illumination, TiO₂/C₃N₄ heterojunction nanotube membrane can generate a photocurrent of about 9 μA/cm², corresponding to a pumping stream of ∼5500 ions per second per nanotube. By changing the position of TiO₂ and C₃N₄, a reverse equivalent ionic current can also be realized. Directional transport of photo generated electrons and holes results in a transmembrane potential, which is the basis of the light-driven ion transport phenomenon. As a proof of concept, we also show that this system can be used for enhanced osmotic energy generation. The artificial light-driven ion transport system proposed here offers a further step forward on the roadmap for the development of ionic photoelectric conversion and their integration in other applications, e.g. water desalination.

中文翻译：

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用于增强渗透能收集的光驱动定向离子传输

光驱动的离子（质子）运输对于绿色植物的光合作用和某些古细菌的太阳能收集都是至关重要的过程。在这里，我们描述了 TiO ₂ /C ₃ N ₄半导体异质结纳米管膜可以实现与生物系统类似的光驱动定向离子传输性能。这种异质结系统可以通过两个简单的沉积步骤来制造。在单边照射下，TiO ₂ /C ₃ N ₄异质结纳米管膜可以产生约9 μA/cm ²的光电流，对应于每纳米管每秒约5500个离子的泵流。通过改变TiO ₂和C的位置₃ N ₄，也可以实现反向等效离子电流。光生电子和空穴的定向传输导致跨膜电位，这是光驱动离子传输现象的基础。作为概念证明，我们还表明该系统可用于增强渗透能的产生。这里提出的人造光驱动离子传输系统为离子光电转换的发展及其在其他应用（例如海水淡化）中的集成提供了进一步的发展。