A Self‐Sustained System for Producing Green Hydrogen via Moisture Power

We report a self‐sustaining system that directly converts atmospheric moisture into green hydrogen, eliminating reliance on intermittent renewables and liquid water sources. The core of the system is a multifunctional hydrogel device that integrates moisture‐enabled electricity generation, atmospheric water harvesting, and electrolysis into a seamless operation. Concerted ion diffusion and active electrode chemistry in the gel yield a stable power output of 1.87 V and 450 μA cm −2 , while its hygroscopic components capture water at 1.318 g g −1 . The harvested water and electricity are used in situ to drive efficient overall water splitting at 1.50 V, catalyzed by a Mo‐FeNi 3 /NiFe 2 O 4 heterostructure catalyst, producing hydrogen at a rate of 2.6 μmol g PPM −1 per cycle. This integrated “moisture‐to‐hydrogen” paradigm offers a scalable, off‐grid solution for continuous and carbon‐neutral hydrogen production.