Green hydrogen produced by water splitting using renewable energy is the most promising energy carrier of the low-carbon economy. However, the geographic mismatch between renewables distribution and freshwater availability poses a significant challenge to its production. Here, we demonstrate a method of direct hydrogen production from the air, namely, in situ capture of freshwater from the atmosphere using hygroscopic electrolyte and electrolysis powered by solar or wind with a current density up to 574 mA cm⁻². A prototype of such has been established and operated for 12 consecutive days with a stable performance at a Faradaic efficiency around 95%. This so-called direct air electrolysis (DAE) module can work under a bone-dry environment with a relative humidity of 4%, overcoming water supply issues and producing green hydrogen sustainably with minimal impact to the environment. The DAE modules can be easily scaled to provide hydrogen to remote, (semi-) arid, and scattered areas.

利用可再生能源分解水产生的绿色氢是低碳经济最有前途的能源载体。然而，可再生能源分布和淡水供应之间的地理不匹配对其生产构成了重大挑战。在这里，我们展示了一种从空气中直接制氢的方法，即使用吸湿性电解质从大气中原位捕获淡水，并通过太阳能或风能进行电解，电流密度高达 574 mA cm ^-2. 该样机已建成并连续运行12天，性能稳定，法拉第效率约为95%。这种所谓的直接空气电解 (DAE) 模块可以在相对湿度为 4% 的极干环境下工作，克服供水问题，可持续生产绿色氢气，对环境的影响最小。DAE 模块可以轻松扩展以向偏远、（半）干旱和分散的地区提供氢气。