A device that can transform CO2 in fuel can prove to be revolutionary. The very idea of using the sun’s rays to get rid of CO2 is great in itself – making that same process create a type of diesel fuel is even better. In theory, waste from inefficient gas cars can be used to make cheaper fuel for more efficient diesel cars, which would drive demand for more diesel cars from cheaper fuel.
The researchers housed a 2-centimetre-square section of material bristling with the tubes inside a metal chamber with a quartz window. They then pumped in a mixture of carbon dioxide and water vapour and placed it in sunlight for three hours.
The energy provided by the sunlight transformed the carbon dioxide and water vapour into methane and related organic compounds, such as ethane and propane, at rates as high as 160 microlitres an hour per gram of nanotubes. This is 20 times higher than published results achieved using any previous method, but still too low to be immediately practical.
If the reaction is halted early the device produces a mixture of carbon monoxide and hydrogen known as syngas, which can be converted into diesel.