Wireless device produces clean fuel from sunlight, carbon dioxide and water

Researchers have developed a self-contained device that converts sunlight, carbon dioxide, and water into carbon-neutral fuel, without requiring additional components or electricity.

The device, developed by a team at the University of Cambridge, is an important step towards achieving artificial photosynthesis – a process mimicking the ability of plants to convert sunlight into energy. It is based on advanced photosheet technology and converts sunlight, carbon dioxide, and water into oxygen and formic acid – a storable fuel that can be used directly or converted to hydrogen.

The results, reported in the newspaper Nature’s energy, represent a new method of converting carbon dioxide into clean fuels. The wireless device could be scaled up and used in energy “farms” similar to solar farms, producing clean fuel using sunlight and water.

Harvesting solar energy to convert carbon dioxide into fuel is a promising way to reduce carbon emissions and move away from fossil fuels. However, it is difficult to produce these clean fuels without unwanted by-products.

“It has been difficult to do artificial photosynthesis with a high degree of selectivity, so that you convert as much sunlight as possible into fuel as you want, rather than ending up with a lot of junk,” said the first author. , Dr. Qian Wang of the Cambridge Chemistry Department.

“In addition, the storage of gaseous fuels and the 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, main author.

In 2019, researchers in Reisner’s group developed a solar reactor based on an “ artificial leaf ” design, which also uses sunlight, carbon dioxide, and water to produce a fuel, called gas. synthesis. The new technology looks and behaves quite similarly to the artificial leaf, but works in a different way and produces formic acid.

While the artificial sheet used solar cell components, the new device does not require these components and relies only on photocatalysts embedded on a sheet to produce a so-called photocatalyst sheet. The sheets are made of semiconductor powders, which can be prepared in large quantities easily and inexpensively.

In addition, this new technology is more robust and produces clean fuel, easier to store and with potential for large-scale petroleum product production. The test unit measures 20 square centimeters, but the researchers say it should be relatively simple to scale it up to several square meters. In addition, formic acid can be accumulated in solution and be chemically converted into different types of fuel.

“We were surprised at how well it performed in terms of selectivity – it produced almost no by-products,” Wang said. “Sometimes things don’t work as well as expected, but it was a rare case where it did work better.”

The carbon dioxide converting cobalt catalyst is easy to manufacture and relatively stable. Although this technology is easier to scale than the artificial leaf, the efficiency still needs to be improved before a commercial deployment can be considered. Researchers are experimenting with a range of different catalysts to improve both stability and efficiency.

The current results were obtained in collaboration with the team of Professor Kazunari Domen of the University of Tokyo, co-author of the study.

Researchers are now working to further optimize the system and improve its efficiency. In addition, they are exploring other catalysts to be used on the device to obtain different solar fuels.

“We hope this technology will pave the way for sustainable and convenient production of solar fuel,” said Reisner.