Researchers say they have developed an artificial "leaf” that can produce fuels such as methane and gasoline from carbon dioxide. The team claimed it is a major step towards using fuels made renewably from sunlight for everything from heating our homes to running cars, without emitting any greenhouse gases.
The breakthrough, published in the Proceedings of the National Academy of Sciences, was led by Peidong Yang and his team at the Kavli Energy NanoSciences Institute at the University of California, Berkeley. It builds on the natural process of photosynthesis, where water and carbon dioxide are turned into sugar – organic fuel – by plants. By tweaking the process, via synthetic photosynthesis, it could be possible to create a whole host of different products.
To demonstrate this is possible, the team were able to make their system produce methane, rather than sugar, from carbon dioxide. Their equipment used a combination of semiconducting nanowires and bacteria to work. Using inorganic catalysts, water was split into hydrogen, which was then used by living cells to convert carbon dioxide into chemical products – in this case, methane.
"We're good at generating electrons from light efficiently, but chemical synthesis always limited our systems in the past,” said Yang in a discussion on the breakthrough. “One purpose of this experiment was to show we could integrate bacterial catalysts with semiconductor technology. This lets us understand and optimize a truly synthetic photosynthesis system.”
A similar system devised by Yang and his team earlier this year produced butanol, a component of gasoline, and various biochemical building blocks. Next, they will attempt to make an entirely synthetic system, without the need for bacteria, that builds on designs in nature to replicate the process of photosynthesis, and ultimately produce liquid fuels that can last months or years.
"This is not about mimicking nature directly or literally," said Ted Sargent, the vice-dean of research for the Faculty of Applied Science and Engineering at the University of Toronto, in the discussion. "Instead, it is about learning nature's guidelines, its rules on how to make a compellingly efficient and selective catalyst, and then using these insights to create better-engineered solutions."
So, you won’t be using artificial leaves to power your home or car just yet. But this could be a significant step in that direction.