Bionic Leaf Uses Sunlight to Make Liquid Fuel
The process could someday replace oil drilling.
Photo: Jessica Polka, Wikimedia Commons Harvard University researchers have found a way to simulate the photosynthesis process that occurs in plants to create a liquid alcohol fuel that someday might replace petroleum. The process utilizes solar energy to split water molecules, and then employs a hydrogen-eating bacteria to produce fuel.
The process is described in a recently published article in the journal Science, whose lead authors include postdoctoral fellow Chong Liu and graduate student Brendan Colón. Daniel Nocera, a co-author of the study and the Patterson Rockwood professor of energy at Harvard, described it in a news release as "a true artificial photosynthesis system."
Fellow co-author, Pamela Silver, a co-founder of Harvard's Wyss Institute for Biologically Inspired Engineering, said that the technology shows the potential for copying biological processes to solve problems.
"The beauty of biology is it's the world's greatest chemist -- biology can do chemistry we can't do easily," she said. "In principle, we have a platform that can make any downstream carbon-based molecule. So this has the potential to be incredibly versatile."
The process, which the Harvard researchers call "bionic leaf 2.0," builds upon a previous effort to develop a practical form of artificial photosynthesis.
That initial project had some bugs to work out. Because the catalyst that it used to split hydrogen and oxygen -- a nickel-molybdenum-zinc alloy -- also created a reactive form of oxygen that harmed the hydrogen-consuming bacteria. To compensate, the scientists had to run that system at an abnormally high voltage, reducing its efficiency.
This time, Nocera explained, the researchers designed a new cobalt-phosphorous alloy catalyst, which doesn't make reactive oxygen. That allowed them to lower the voltage, and that led to a dramatic increase in efficiency."
Bionic leaf 2.0 can convert solar energy into fuel with about a 10 percent efficiency rate, far above the 1 percent efficiency achieved by fast-growing plants.
As an added bonus, in addition to fuel, the system also produces PHB, a bio-plastic precursor.
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