In the future, instead of driving to gas stations, you might make your own solar-powered fuel at home—assuming that you don't have a self-driving electric car by that point.
Researchers at Harvard University have demonstrated a new artificial photosynthesis system that makes fuel using nothing but solar power, water, air, and bacteria. The "artificial leaf"—which looks basically like a jar with wires coming out of it—can convert solar energy to biomass 10 times more efficiently than most plants.
An earlier version of the leaf used solar power to split water molecules, creating hydrogen fuel. But because there are few hydrogen cars on the road, the team decided to go further and develop a system that could create fuel that would work in current vehicles.
"We obviously are highly dependent on certain kinds of fuel," says Pamela Silver, a Harvard biochemistry professor who collaborated on the new system with energy professor Daniel Nocera. "Our infrastructure is built around fossil-based fuels, we have a centralized distribution system, and hydrogen is not compatible with the current infrastructure."
The system uses a catalyst, cobalt phosphate, that can split water into hydrogen and oxygen when it's in sunlight. It's the same thing that plants do as they begin the process of natural photosynthesis. While plants would use that energy to make carbohydrates, the new system uses bacteria to convert the hydrogen into PHB, a molecule that can then be turned into fuel.
When it's burned, like regular gas, it creates pollution. But because the process pulls the same amount of carbon from the atmosphere, it isn't technically making pollution worse. "In principle, it's carbon-neutral, because you're fixing carbon from the atmosphere and then burning it back," says Silver.
The same process could also be used to make other products, such as plastics that are normally made from petroleum. "Bacteria can be used to make lots of different things," she says. "That's the beauty of using biology—[bacteria are] great chemists."
The researchers plan to keep scaling the system up so that it can be commercialized.
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