A team of researchers from the University of Cambridge took a notable step towards achieving artificial photosynthesis. It is mainly based on advanced photosheet technology, fundamentally this technology converts sunlight, CO2, and water into oxygen molecules and formic acid, which is a storable fuel that is also convertible to hydrogen.
The research published in the Nature Energy journal details a novel conversion method that produces clean fuels from carbon dioxide. It could also be scaled up and be assembled into something similar to a solar panel farm. The main problem with artificial photosynthesis has been the unwanted byproducts of the chemical processes.
The first author Dr. Qian Wang from the Department of Chemistry told Cambridge News, “It’s been difficult to achieve artificial photosynthesis with a high degree of selectivity. Selectivity here meaning "converting as much of the sunlight as possible into the fuel you want, rather than be left with a lot of waste.”
And Prof. Erwin Reisner, the senior author of the paper added, “In addition, storage of gaseous fuels and separation of by-products can be complicated – we want to get to the point where we can cleanly produce a liquid fuel that can also be easily stored and transported,” said Professor Erwin Reisner, the paper’s senior author.
In 2019, another group of Reisner developed a similar solar-to-chemical energy converter which they likened to an artificial leaf. It used the same components, water, CO2, and sunlight. The difference is the fuel it produced: syngas. We won't go into detail on syngas here but it consists primarily of hydrogen, carbon monoxide, and sometimes carbon dioxide.
The artificial leaf design required solar cell components; the new device, however, doesn't require such components, instead it relies on photocatalyst sheets only. These sheets are made of semiconductor powders which can be prepared in bulk easily and are cost-efficient. What's more, it's stability and selectivity pretty much baffled the research team.
Wang said, “We were surprised how well it worked in terms of its selectivity – it produced almost no by-products,” and added, “Sometimes things don’t work as well as you expected, but this was a rare case where it actually worked better.”
The cobalt-based CO2 catalyst is relatively simple and easy to manufacture. Still, further research is necessary until we see real-life applications for the device. The researchers are working to improve stability and efficiency.