{"id":8316,"date":"2016-06-15T01:51:51","date_gmt":"2016-06-15T01:51:51","guid":{"rendered":"http:\/\/www.kurzweilai.net\/?p=281671"},"modified":"2016-06-17T02:20:41","modified_gmt":"2016-06-17T02:20:41","slug":"bionic-leaf-2-0","status":"publish","type":"post","link":"https:\/\/hoo.central12.com\/fugic\/2016\/06\/15\/bionic-leaf-2-0\/","title":{"rendered":"Bionic leaf 2.0"},"content":{"rendered":"
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Bionic leaf 2.0: An artificial photosynthesis system (credit: Jessica Polka)<\/p><\/div>\n

Harvard scientists have created a system a system that uses solar energy plus hydrogen-eating bacteria to produce liquid fuels with 10 percent efficiency, compared to the 1 percent seen in the fastest-growing plants.<\/p>\n

The system, co-created by Daniel Nocera<\/a>, the Patterson Rockwood Professor of Energy at Harvard University, and\u00a0Pamela Silver<\/a>, the Elliott T. and Onie H. Adams Professor of Biochemistry and Systems Biology at Harvard Medical School, uses solar energy to split water molecules into hydrogen and oxygen molecules.<\/p>\n

A paper on the research was published June 3 in\u00a0Science<\/em><\/a>.<\/p>\n

\u201cThis is a true artificial photosynthesis system,\u201d Nocera said. \u201cBefore, people were using artificial photosynthesis for water-splitting, but this is a true A-to-Z system, and we\u2019ve gone well over the efficiency of photosynthesis in nature.\u201d<\/p>\n

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“What we’ve invented is an artificial leaf. You just drop it in water and sunlight hits it, and out one side comes hydrogen and out the other side comes oxygen.” — Daniel Nocera<\/p><\/div>\n

\u201cThe beauty of biology is it\u2019s the world\u2019s greatest chemist: Biology can do chemistry we can\u2019t do easily,\u201d said Silver, who is also a founding core member of the\u00a0Wyss Institute<\/a>\u00a0at Harvard University. “In principle, we have a platform that can make any downstream carbon-based molecule. So this has the potential to be incredibly versatile.\u201d<\/p>\n

Dubbed \u201cbionic leaf 2.0,\u201d the new system builds on previous work by Nocera, Silver and others, which faced a number of challenges. Mainly, the catalyst they used to produce hydrogen (a nickel-molybdenum-zinc alloy) also created reactive oxygen species<\/a> — molecules that attacked and destroyed the bacteria\u2019s DNA. To avoid that problem, researchers were forced to run the system at abnormally high voltages, resulting in reduced efficiency.<\/p>\n

<\/strong>Ready for commercial applications, with a new model
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\u201cFor this paper, we designed a new cobalt-phosphorus alloy catalyst, which we showed does not make reactive oxygen species,\u201d Nocera said. \u201cThat allowed us to lower the voltage, and that led to a dramatic increase in efficiency.\u201d<\/p>\n

Nocera and colleagues were also able to expand the portfolio of the system to include isobutanol (a solvent) and isopentanol (used in geothermal power production to drive turbines), along with PHB, a bioplastic precursor.<\/p>\n

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\u201cInstead of having a gas station, the Sun is hitting your house, you have the artificial leaf, you could be generating your own fuel.\u201d \u2014 Daniel Nocera (credit: Rose Lincoln\/Harvard Staff Photographer)<\/p><\/div>\n

The new catalyst’s chemical design also allows it to \u201cself-heal,\u201d meaning it won\u2019t leach material into solution — it’s biologically compatible.<\/p>\n

Nocera said the system is already effective enough to consider possible commercial applications but within a different model for technology translation. \u201cIt\u2019s an important discovery… [that] can do better than photosynthesis,\u201d Nocera said. \u201cBut I also want to bring this technology to the developing world.\u201d<\/p>\n

Working in conjunction with the First 100 Watts Project at Harvard, which helped fund the research, Nocera hopes to continue developing the technology and its applications in nations such as India with the help of that country\u2019s scientists.<\/p>\n

In many ways, Nocera said, the new system marks fulfillment of the promise of his \u201cartificial leaf,\u201d which used solar power to split water and make hydrogen fuel (see \u2018Artificial leaf\u2019 harnesses sunlight for efficient, safe hydrogen fuel production<\/a>).<\/p>\n

\u201cIf you think about it, photosynthesis is amazing,\u201d he said. \u201cIt takes sunlight, water and air\u2014and then look at a tree. That\u2019s exactly what we did, but we do it significantly better, because we turn all that energy into a fuel.\u201d<\/p>\n

The work, a direct result of the First 100 Watts Project established at Harvard University, was was supported by Office of Naval Research Multidisciplinary University, Research Initiative Award, Air Force Office of Scientific Research Grant, and the Wyss Institute for Biologically Inspired Engineering. The Harvard University Climate Change Solutions Fund is supporting ongoing research into the \u201cbionic leaf\u201d platform.<\/p>\n