A device that can harvest water from the air and provide hydrogen fuel?"entirely powered by solar energy?"has been a dream for researchers for decades. Now, EPFL chemical engineer Kevin Sivula and his team have made a significant step towards bringing this vision closer to reality. They have developed an ingenious yet simple system that combines semiconductor-based technology with novel electrodes that have two key characteristics: they are porous, to maximize contact with water in the air; and transparent, to maximize sunlight exposure of the semiconductor coating. When the device is simply exposed to sunlight, it takes water from the air and produces hydrogen gas. The results are published on 4 January 2023 in Advanced Materials. What's new? It's their novel gas diffusion electrodes, which are transparent, porous and conductive, enabling this solar-powered technology for turning water ?" in its gas state from the air ?" into hydrogen fuel.