New artificial leaf creates fuel using CO2, sunlight

Washington: Scientists have developed “artificial leaves,” potentially game- changing solar cells that cheaply and efficiently convert atmospheric carbon dioxide directly into usable hydrocarbon fuel using sunlight. Unlike conventional solar cells, which convert sunlight into electricity that must be stored in heavy batteries, the new device essentially does the work of plants, converting atmospheric CO2 into fuel. A solar farm of such “artificial leaves” could remove significant amounts of carbon from the atmosphere and produce energy- dense fuel efficiently. “The new solar cell is not photovoltaic — it’s photosynthetic,” said Mr Amin Salehi- Khojin, professor at University of Illinois at Chicago. “Instead of producing energy in an unsustainable one- way route from fossil fuels to greenhouse gas, we can now reverse the process and recycle atmospheric carbon into fuel using sunlight,” he said. While plants produce fuel in the form of sugar, the artificial leaf delivers syngas, or synthesis gas, a mixture of hydrogen gas and carbon monoxide. Syngas can be burned directly, or converted into diesel or other hydrocarbon fuels at a cost comparable to a gallon of gasoline. Chemical reactions that convert CO2 into forms of carbon that can be burnt are called reduction reactions, the opposite of oxidation or combustion. Engineers have been exploring different catalysts to drive CO2 reduction, but so far such reactions have been inefficient and rely on expensive precious metals such as silver, Mr Salehi- Khojin said.