A research team led by pioneering clean energy technology developer and MIT professor Daniel Nocera has developed an ‘artificial leaf’ that like its namesake captures energy from sunlight and produces electricity that it then turns into chemical fuel — hydrogen and oxygen gas.
Made up of a thin sheet of silicon solar cell material bonded either side with thin sheets of catalytic cobalt and nickel-molybdenum-zinc, when placed in an ordinary container of water, the ‘artificial leaf’s’ solar photovoltaic (PV) cells generate an electric current which catalysts bonded to the solar cell sheet use to produce oxygen and hydrogen gas.
Collected, stored and coupled to hydrogen fuel cells, the gases could be used as an energy carrier that would create electricity on demand at scales ranging from individual home use on up to utility-scale power plants.
“I think there’s going to be real opportunities for this idea,” Nocera told MIT News’ David L. Chandler. “You can’t get more portable — you don’t need wires, it’s lightweight…You just drop it in a glass of water, and it starts splitting it.”
The ‘artificial leaf’ converted 2.5% of incident sunlight into electricity, which is low compared with the 10% and higher energy conversion efficiencies found in today’s solar panels, but Nocera and his team are working at boosting it. Connecting wires to connect the catalysts to the solar cell membrane raised its conversion efficiency to 4.7%.
Moreover, the materials used to manufacture the ‘leaf’ are common and relatively abundant in nature, which offers the potential of producing them cheaply and on a large-scale, while the ‘artificial leaf small size makes it extremely portable.
Nocera and his team are also looking at the possibility of breaking the ‘artificial leaf’ down into much smaller particles that can capture the energy in sunlight to split water molecules akin to the way this is done in nature by algae. Doing this would increase the surface area available to absorb sunlight, hence raising the system’s energy conversion efficiency.
Separating and collecting the two gas streams produced would be more difficult with ‘artificial algae’ as compared to the ‘artificial leaf,’ which, along with a means of storing the gases, is the next step Nocera and his team are looking to take to further develop the clean energy system.
Commenting on the research development, Imperial College of London biochemist and professor James Barber said, “This is a major achievement, which is one more step toward developing cheap and robust technology to harvest solar energy as chemical fuel…
“There is no doubt that their achievement is a major breakthrough which will have a significant impact on the work of others dedicated to constructing light-driven catalytic systems to produce hydrogen and other solar fuels from water.
Tempering enthusiasm a bit, he added that, “There will be much work required to optimize the system, particularly in relation to the basic problem of efficiently using protons generated from the water-splitting reaction for hydrogen production.”
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