Scientists have found a way to purify dirty water and generate hydrogen fuel at the same time. The new device, dubbed an “artificial leaf”, can not only create clean water but also clean fuel, say researchers. And, even better, it’s solar-powered and can float.
Off-grid and dirty? No problem
Inspired by the way plants turn sunlight into food, through photosynthesis, the device breaks water down into hydrogen and oxygen, a known process but one that scientists have previously found must begin with completely pure water to avoid contamination and unfavourable chemical reactions.
Now though, any water source will do and, thanks to solar power, it’s not even necessary to be on the electricity grid to generate the pure water and hydrogen fuel. A research team at the University of Cambridge, who were partly supported by the European Commission’s Horizon 2020 programme and the European Research Council, have proof of concept that their latest solar-powered artificial leaf, reported in Nature Water journal, can “split water” to produce green hydrogen from any water source, including “highly polluted water” which is purified along the way. That includes seawater and the nearby River Cam.
A solar device developed by @ReisnerLab scientists that can turn polluted or sea water into clean water and green hydrogen fuel could be a ‘game-changer’ in the bid to build a sustainable and healthier future, says St John’s academic Prof Erwin Reisner.https://t.co/EPBMbHL6yw pic.twitter.com/KfjXkcrDXE— St John’s College, Cambridge (@stjohnscam) November 14, 2023
Solving two problems at once
The potentially life-changing implications for “remote and developing regions, where clean water is relatively scarce and the infrastructure for water purification is not readily available” are huge. “A device that could work using contaminated water could solve two problems at once,” said co-lead author Ariffin Mohamad Annuar. “It could split water to make clean fuel, and it could make clean drinking water.”
The researchers have also found a way to make more efficient use of the sun’s light, by using parts of the light spectrum that are usually “wasted”. The water-splitting that creates hydrogen uses absorbed white UV light, while the energy in the remainder of the spectrum vaporises and purifies the water.
“We’re making better use of the light – we get the vapour for hydrogen production, and the rest is water vapour,” said co-lead author Doctor Chanon Pornrungroj. “This way, we’re truly mimicking a real leaf, since we’ve now been able to incorporate the process of transpiration.”
Water and fuel poverty
With 1.8 billion people unable to access clean drinking water at home, and many people around the world facing deadly domestic air pollution due to a lack of clean fuel to cook with and heat their homes, the new “artificial leaf” is one of the “solutions we will need if we’re going to develop a truly circular economy and sustainable future,” said Professor Erwin Reisner, who led the research. “The climate crisis and issues around pollution and health are closely related, and developing an approach that could help address both would be a game-changer for so many people.”