Researchers at Harvard have developed a more efficient version of the bionic leaf, which can turn sunlight and water into electricity and liquid fuels.
Over the last few years, great strides have been made in creating artificial leaves that mimic the ability of their natural counterparts to produce energy from water and sunlight. In 2011, the first cost-effective, stable artificial leaves were created, and in 2013, the devices were improved to self-heal and work with impure water. Now, scientists at Harvard have developed the “bionic leaf 2.0,” which increases the efficiency of the system well beyond nature’s own capabilities, and used it to produce liquid fuels for the first time.
The project is the work of Harvard University’s Daniel Nocera, who led the research teams on the previous versions of the artificial leaf, and Pamela Silver, Professor of Biochemistry and Systems Biology at Harvard Medical School.
Like the previous versions, the bionic leaf 2.0 is placed in water and, as it absorbs solar energy, it’s able to split the water molecules into their component gases, hydrogen and oxygen. These can be harvested and used in fuel cells to generate electricity, but now, with the help of an engineered bacteria, the hydrogen can be used to produce liquid fuels.
Where this latest device beats the efficiency of previous tests – and nature itself – is down to the catalyst that produces the hydrogen. In earlier versions, the nickel-molybdenum-zinc alloy catalyst used to produce the hydrogen also created reactive oxygen species, which would attack and destroy the bacteria’s DNA. As a result, the researchers were forced to run the system at a higher voltage to overcome the issue, which led to a reduction in the overall efficiency.
The rest of the article can be viewed here: http://www.gizmag.com/bionic-leaf-2-more-efficient-photosynthesis/43691/