Part microbe, part machine: bionic leaf sucks up sunlight and carbon dioxide to make liquid fuel

A team of scientists at Harvard University says it has come up with a bionic leaf — a system that could use solar power and hydrogen-eating bacteria to generate liquid fuel.

The findings, described in the journal Science, offer an alternative path to making carbon-neutral solar fuels.

Part microbe and part machine, the bionic leaf marks a tenfold improvement on the researchers’ previous version and could be used to generate all kinds of products, from the precursors for bioplastics to fuel.

“This work is quite significant. … The high performance of this system is unparalleled by any other CO2 reducing system,” Peidong Yang, a University of California, Berkeley chemist and MacArthur “genius” grant winner who was not involved in the paper, said in an email. “In addition, being able to do this at low pressures and at high oxygen concentrations represents another major advancement.”

Burning fossil fuel is a dirty process. It pulls out hydrocarbons stored safely in the ground and sends carbon dioxide into the air, releasing a molecule that is contributing both to rising global temperatures and ocean acidification. So getting onto a zero-carbon energy system that uses a totally clean fuel, or at least a carbon-neutral system that recycles the carbon in the air, is of serious importance in the coming decades, scientists say.

Study co-author Daniel Nocera, a Harvard chemist, is one of those scientists: He famously made what was dubbed the “artificial leaf” — a semiconductor wafer coated in a catalyst that could be dropped in water and produce hydrogen gas.

But those systems aren’t commercially competitive with fossil fuels yet — and there’s no large-scale infrastructure to manage and store it. So some scientists have tried to make hydrocarbons using water, sunlight and carbon dioxide — which has turned out to be an exceedingly complex challenge.