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Latest bionic leaf now 10 times more efficient than natural photosynthesis

Latest bionic leaf now 10 time...
Researchers at Harvard have developed a more efficient version of the bionic leaf, which can turn sunlight and water into electricity and liquid fuels
Researchers at Harvard have developed a more efficient version of the bionic leaf, which can turn sunlight and water into electricity and liquid fuels
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Pamela Silver, the Elliott T. and Onie H. Adams Professor of Biochemistry and Systems Biology at Harvard Medical School, is a co-creator of the bionic leaf 2.0
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Pamela Silver, the Elliott T. and Onie H. Adams Professor of Biochemistry and Systems Biology at Harvard Medical School, is a co-creator of the bionic leaf 2.0
Daniel Nocera, the Patterson Rockwood Professor of Energy at Harvard University, is a co-creator of the bionic leaf 2.0
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Daniel Nocera, the Patterson Rockwood Professor of Energy at Harvard University, is a co-creator of the bionic leaf 2.0
Researchers at Harvard have developed a more efficient version of the bionic leaf, which can turn sunlight and water into electricity and liquid fuels
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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.

"For this paper, we designed a new cobalt-phosphorous alloy catalyst, which we showed does not make reactive oxygen species," says Nocera. "That allowed us to lower the voltage, and that led to a dramatic increase in efficiency."

With this new catalyst, the system is able to convert sunlight into biomass with 10 percent efficiency, which is 10 times that of even the most efficient plants. But that's not the only potential application for the technology.

"The beauty of biology is it's the world's greatest chemist — biology can do chemistry we can't do easily," says Silver. "In principle, we have a platform that can make any downstream carbon-based molecule. So this has the potential to be incredibly versatile."

Already, the researchers have demonstrated how the system can be used to create compounds such as isobutanol, isopentanol and PHB, a bio-plastic precursor. Additionally, the catalysts are biologically compatible as they "self heal", so they don't leech material into a solution.

While there is likely more room for further increases in efficiency, the team says it currently works well enough to consider commercial applications. As he discussed in previous years, Nocera's plans for the technology include using it in developing countries as an inexpensive source of renewable energy, which could power individual homes.

The team's results appear in the latest issue of the journal Science, and Nocera discusses the project in the video below.

Source: Harvard

Bionic Leaf Turns Sunlight Into Liquid Fuel

8 comments
Mzungu_Mkubwa
So, why does it have to be a solar cell as the electrical source? Why not your car's alternator? Then simply feed the resulting hydrogen and oxygen into your vehicle's air intake and at least partially shift over to burning this potent mixture directly in I/C. (Yes, this has been done, and debunked by many. But really, the "water-for-gas" crowd is mostly just missing an efficient catalyst for the electrolysis step, right? Once this aspect is refined to max efficiency, then burning this directly in our vehicles can at least bridge the gap until we can switch entirely away from fossil fuels. Or what else am I missing?)
S Michael
MzunguMkubwa.... You answered your own question. Switching from fossil fuels...to much money and power to happen. This along with battery development will be crushed or delayed for a long time.
Bob Flint
This does take resources and energy to produce energy, even if your process is 10% efficient versus natures 1% whereas mother natures leaves in billions of trees don't cost anything...
Redmercury
Mzunga why would you want to integrate these with your car? Maybe I'm missing your point, but it seems like using this as a home energy system would be good enough, and simpler. Just refill your cars tank from home. Bob I don't see your point. For a tree to make leaves takes energy, the only thing that's free is the sunlight and some cool osmotic tricks to minimize energy loss from moving nutrients. From a human perspective it still takes energy to harvest the energy of a tree. I don't need to get into how this is different from harvesting biomass from plants for energy. The really cool thing about this technology is that it minimizes the need for batteries as a renewable energy system.
physics314
So, this "leaf" does the same water splitting as a PV cell + electrolyzer, just at 1/2 the efficiency and 10x the cost? A miracle indeed!
DNKXP
Mzungu, the "hydrogen on demand" system of electrically splitting water into oxygen and hydrogen for a supplemental engine fuel in order to decrease fossil fuel consumption is an inneficient and unnecessary process. To create enough hydrogen/oxygen mix to be practical requires large amounts of electricity, placing an unnecessary drain on the vehicle charging system, and requires tanks, hoses, and a harsh chemical catalyst. A much more intelligent way to accomplish the process is to use water injection directly into the air intake. When the water enters the combustion chamber, the high temperature (1600° Fahrenheit or so) immediately vaporises the fluid into it's constituent components of two oxygen atoms and one hydrogen atom, both of which are highly flammable, with or without each other. Remember, this is not a new technology, it was developed to use in P51 Mustang fighter planes in WW2.
Chizzy
DNKXP The P51 boost system did not use just water, it was a water/methanol mix. The water did not act as fuel, it acted as coolant to prevent the methanol from going BOOM.
Paul Muad'Dib
This could be bad for Intelligent Design.