A team of chemical engineers has developed a solar-powered artificial leaf using a unique transparent and porous electrode. This invention can extract water from the atmosphere and convert it into hydrogen fuel. The technology uses semiconductors and can be easily scaled up.
Chemical engineers at the École Polytechnique Fédérale de Lausanne (EPFL) have developed a solar-powered technology that can convert water from the air into hydrogen fuel using a transparent and porous electrode. This novel gas diffusion electrode is conductive, and can be coated with a light-harvesting semiconductor material that acts like an artificial leaf, absorbing sunlight and water to produce hydrogen gas. The research team, in collaboration with Toyota Motor Europe, was inspired by the process of photosynthesis in plants, which converts carbon dioxide and water into sugars and starches using sunlight. EPFL engineer and principal investigator of the study, Sivula, believes this technology could help realize a sustainable society by developing economically competitive ways to produce solar fuels. Now the researchers are focusing on optimizing the system for scalability and efficiency.
The team overcame the challenges of creating transparent gas diffusion electrodes, by using a 3-dimensional mesh of felted glass fibers as the substrate, which is opaque to sunlight. They started with a type of glass wool, which is made of quartz fibers, and processed it into felt wafers by fusing the fibers together at high temperature. They then coated the wafer with a transparent thin film of fluorine-doped tin oxide, which is known for its excellent conductivity, robustness and ease to scale-up. This resulted in a transparent, porous, and conducting wafer which maximizes contact with water molecules in the air, and allows sunlight to penetrate the electrode.
Previous research had already shown that it was possible to perform artificial photosynthesis by generating hydrogen fuel from liquid water and sunlight using a device called a photoelectrochemical (PEC) cell. However, these devices are complicated to make in large areas and require liquid. Sivula and the team wanted to adapt this PEC technology to harvest humidity from the air instead, which led to the development of their new gas diffusion electrode. The team is now focusing on further optimizing the system by studying the ideal fiber size, pore size, semiconductors, and membrane materials to make it more efficient and scalable.
The team’s research is part of the EU project called “Sun-to-X,” which is focused on advancing this technology, and developing new ways to convert hydrogen into liquid fuels. The development of transparent and scalable gas diffusion electrodes could open new horizons for a wide range of applications in solar-driven hydrogen production, and is an important step towards achieving a sustainable society that uses renewable energy sources.
Another potential application for this technology could be in the field of portable or mobile energy systems. For example, a portable device based on this technology could potentially be used to produce hydrogen fuel for use in vehicles or portable generators. Such a device could be powered by solar energy and be capable of extracting water vapor from the air, even in areas where water resources are limited. This could prove useful for military, emergency and remote operations, where access to clean and reliable energy is essential.
Another potential application could be in the field of hydrogen fuel production for residential use. A device based on this technology could potentially be integrated into homes, providing a clean and renewable source of energy for heating, cooking, and powering electronic devices.
It’s also worth mentioning that there are other technologies being developed to extract water vapor from the air and convert it into drinking water as well, this technology could be integrated with those to provide a comprehensive solution to lack of clean water and energy in arid regions.
It’s important to note that while this technology holds promise and exciting potential, it’s still early in development and a lot of research is needed to optimize the system, improve its efficiency, and make it economically viable at scale, before it could be considered for commercial or practical usage.