“Artificial Leaf” Assures Fuel from Sunlight and Water

It took millions of years of evolution for plants to be the most efficient harvesters of solar energy on the planet. Much experimentation is underway into ways to artificially mimic photosynthesis in devices like artificial leaves, but scientists at the Harvard University have successfully produced something they’re calling an “artificial leaf.” This artificial leaf harvests energy from sunlight through a chemical process called photosynthesis which can turn sunlight into the chemical fuel that can be stored and used later, allowing to run low-powered electrical devices.
The artificial leaf is a silicon solar cell with multiple catalytic elements bonded onto its two sides, and it needs no wires or control circuits to work. Researchers claim that it can convert solar energy to biomass with 10 percent efficiency, far above the 1% seen in the fastest-growing plants. This efficiency rate is much higher than naturally occurring photosynthesis, which converts only 1 percent of solar power into the carbohydrates consumed by plants, and it could be a milestone in the shift away from fossil fuels.
Daniel Nocera, a professor at Harvard University, who has pioneered the use of artificial photosynthesis, says that this system devised by him with his colleague Pamela Silver completes the process of producing liquid fuel from carbon dioxide, water, and sunlight. According to the Nocera, “This is a true artificial photosynthesis system before people were using artificial photosynthesis for water-splitting, but this is a true A-to-Z photosynthesis system, and we’ve gone well over the efficiency of photosynthesis in nature.”
“While the study shows the system can be used to generate usable fuels, its potential doesn’t end there,” said Silver, who is also a Founding Core Member of the Wyss Institute at Harvard University.
Dubbed “bionic leaf 2.0,” the new system builds on previous work by Nocera, was full of many obstacles. The major one among those challenges was the fact that the catalyst used to produce hydrogen — a nickel-molybdenum-zinc alloy — also created reactive oxygen molecules that attacked and destroyed the bacteria’s DNA. To avoid this problem, researchers were compelled to run the system at high voltages, resulting in reduced efficiency. Nocera said the system is already capable enough to consider possible commercial applications but within a different model for technology translation. Though there may yet be scope for further increases in efficiency.
Working in association with the First 100 Watts program at Harvard, which helped fund this research, Nocera wishes to continue improving the technology and its applications in nations like India with the aid of their scientists.

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