Photosynthesis has long been looked at as the gold standard for turning sunlight into energy and it only makes sense to look to plants for inspiration when building a new clean technology.
Harvard and many other labs have been working on artificial leaves for years. Usually the result is a solar technology that when submerged in water or connected to a water source can split the water molecules into oxygen and hydrogen for use in a fuel cell.
Last year, Harvard debuted their bionic leaf which goes beyond that and turns sunlight into liquid fuel. The system uses solar energy to split the water molecules, but also contains hydrogen-eating bacteria that produces liquid fuel. The bionic leaf has now gotten a significant upgrade and has far surpassed the ability of plants themselves to produce fuel from sunlight.“This is a true artificial photosynthesis system,” said Professor of Energy Daniel Nocera, one of the lead researchers. “Before, people were using artificial photosynthesis for water-splitting, but this is a true A-to-Z system, and we’ve gone well over the efficiency of photosynthesis in nature.”
The new system converts sunlight into biomass at an efficiency of 10 percent, which is 10 times better than the one percent achieved by the fastest growing plants.
The improvements don't end there. The previous version of the bionic leaf could take solar energy and turn it into isopropanol, but the catalyst used to produce hydrogen also produced a reactive oxygen species that attacked the bacteria's DNA.
This time with bionic leaf 2.0, they're using a new catalyst that doesn't produce the reactive oxygen, making the system far more efficient and the new system can now produce many more fuels like isobutanol, isopentanol and PHB, a bio-plastic precursor.
“The beauty of biology is it’s the world’s greatest chemist — biology can do chemistry we can’t do easily,” said Professor of Biochemistry Pamela Silver, co-creator of the system. “In principle, we have a platform that can make any downstream carbon-based molecule. So this has the potential to be incredibly versatile.”
The new catalyst came with another bonus benefit -- it can self-heal so it won't leach material into the solution.
The next step is to further develop the technology into a commercial version as well as one that can be used in the developing world.
You can watch a short video about the new and improved bionic leaf 2.0 below.