March 5, 2009
Study: Sunlight can turn CO2 into methane
U.S. scientists say dual catalysts might turn carbon dioxide and water vapor into methane and other hydrocarbons using titania nanotubes and solar power.
Burning fossil fuels such as oil, gas and coal release large amounts of carbon dioxide into the Earth's atmosphere. But Pennsylvania State University researchers said rather than contributing to global climate change, producers could convert the CO2 into a wide variety of hydrocarbons.
Recycling of carbon dioxide via conversion into a high energy-content fuel suitable for use in the existing hydrocarbon-based energy infrastructure is an attractive option. However, the process is energy intense and useful only if a renewable energy source can be used for the purpose, the researchers said.
Professor Craig Grimes and his team said they used titanium dioxide nanotubes doped with nitrogen and coated with a thin layer of copper and platinum to convert a mixture of carbon dioxide and water vapor into methane. Using outdoor, visible light, they reported a 20-times higher yield of methane than previously published attempts conducted in laboratories using intense ultraviolet exposures.
Grimes said solar power is necessary since at least eight photons are required for each molecule for the reaction to occur.
The research that included Oomman Varghese, Maggie Paulose, and Thomas LaTempa was reported in a recent issue of the journal Nano Letters.