by A team of researchers from the University of Cambridge has developed a groundbreaking solar-powered device that can convert polluted water or seawater into clean hydrogen fuel and drinking water. The device, which works with any open water source and does not require external power, has the potential to be used in resource-limited or remote areas.
Traditionally, the process of converting sunlight into storable hydrogen fuel, known as photocatalytic water splitting, requires pure water and land for installation. Additionally, it generates unusable waste heat. In order to make the process more sustainable, the researchers sought to develop a photocatalytic device that could use untreated water sources such as rivers, seas, water reservoirs, or industrial wastewater.
Inspired by the process of photosynthesis in plants, the researchers created a solar-powered device that can simultaneously produce clean hydrogen fuel and drinking water from contaminated water or seawater. The key challenge in integrating solar fuel production and water production in a single device lies in the need for pure water to prevent catalyst poisoning or unwanted chemical reactions.
Unlike previous devices that produced green hydrogen fuel from clean water sources, the researchers wanted their device to be able to use contaminated water, making it suitable for regions with limited access to clean water. In these remote or developing areas where clean water is scarce and water purification infrastructure is lacking, water splitting becomes extremely challenging. Thus, a device that can work with contaminated water would not only produce clean fuel but also provide clean drinking water, solving two problems simultaneously.
The researchers achieved this by depositing a UV-light-absorbing photocatalyst on an infrared-light-absorbing nanostructured carbon mesh, which acts as a good absorber of both light and heat. The carbon mesh, treated to repel water, allows the photocatalyst to float and remain separate from the water below, ensuring that contaminants do not interfere with its functionality. This configuration also enables the device to utilize more of the sun’s energy, making it more efficient.
The device utilizes a light-driven process for making solar fuels, harnessing a small portion of the solar spectrum. To make better use of the remaining spectrum, the researchers incorporated a white, UV-absorbing layer on top of the floating device for hydrogen production. The rest of the solar spectrum is transmitted to the bottom of the device, where it vaporizes the water. This approach closely mimics transpiration, the natural process of water movement and evaporation in plants.
The researchers tested the device using real-world open water sources, including the River Cam in central Cambridge and turbid industrial waste from the paper industry. Even in artificial seawater, the device maintained 80% of its initial performance after 154 hours, demonstrating its tolerance to pollutants. The floating design of the device allows it to function effectively in cloudy or muddy water, making it highly versatile.
While the device is currently a proof of concept, the researchers believe it has the potential to address sustainability and circular economy issues. Developing solutions like this is crucial for building a truly circular economy and sustainable future. By tackling the climate crisis, pollution, and health issues simultaneously, this device could be a game-changer for many people, said Erwin Reisner, a corresponding author of the study.
As further research and development are conducted, this solar-powered device could offer a promising solution for producing clean energy and clean drinking water in regions where these resources are scarce or contaminated. Its versatility and tolerance to pollutants make it a valuable tool in building a more sustainable and resilient future.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
