An artificial 'leaf' for solar power storage

MIT researchers present a photosynthesis-inspired solar cell at an American Chemical Society meeting. Could it one day bring a cheap form of solar power to rooftops around the world? They hope so.

Leaves are nature's solar cells. They capture sunlight in order to provide energy for the plant through photosynthesis. As they do so, water molecules split into hydrogen and oxygen.

In search of renewable sources of energy, scientists have been looking to mimic photosynthesis for some time. Just yesterday, researchers at an American Chemical Society meeting discussed their new artificial 'leaf.' At about the size of a playing card (but even thinner), the so-called leaf allows solar power to be stored in the form of a hydrogen fuel cell.

With the help of sunlight and catalysts of nickel and cobalt, the electronic silicon device splits water into oxygen and hydrogen, which can then generate electricity. The chemists, from the Massachusetts Institute of Technology, hope their artificial leaf could bring sun-derived hydrogen power to off-grid locales in need of clean, cheap power.

A picture of the device was not provided, but the idea is to place the leaf in a gallon of water (and dirty water apparently works, too) and expose it to sunlight whereby a photosynthetic-like reaction will occur. The resulting hydrogen and oxygen are stored in tanks for use later, perhaps when the sun isn't shining.

Government scientists at the National Renewable Energy Laboratory created a similar leaf in the late nineties. Comprised of expensive materials, that photoelectrolysis device, however, wasn't feasible economically. It also had a short lifespan, petering out in less than a day. The MIT group says their leaf is cheaper and more durable, lasting 45 hours before experiencing a drop in activity.

Daniel Nocera, lead researcher and professor of chemistry at MIT, said in a statement:

A practical artificial leaf has been one of the Holy Grails of science for decades. We believe we have done it. The artificial leaf shows particular promise as an inexpensive source of electricity for homes of the poor in developing countries. Our goal is to make each home its own power station. One can envision villages in India and Africa not long from now purchasing an affordable basic power system based on this technology.

According to Nocera, his fake foliage is 10 times more efficient than real leaves.

Yet research is still in its early days. Even so, Nocera's start-up Sun Catalytix, as reported by Live Mint last week, has signed a deal with the Indian company Tata group that could try to bring the technology to market.

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Image 1: Flickr/- POD -
Image 2: Donna Coveney

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