Creating Fuel From Carbon Dioxide
Chemists Develop Device That Creates Fuel From CO2
A device that captures energy from the sun offers a sustainable alternative by splitting carbon dioxide into carbon monoxide and oxygen and converting it into fuel.
Carbon dioxide is an important green house gas that is a component of the carbon cycle. Plants pull carbon dioxide out of the atmosphere and remove the carbon converting it into oxygen, thanks to chlorophyll.
- Natural sources of CO2 include forest fires, decomposition, respiration and volcanoes. Human activity is responsible for higher levels of CO2 that contribute to global warming. Man made sources include the clearing of forests, burning fossil fuels and various forms of transportation. The problem with too much CO2 is that it allows the sun in but does not allow the heat to escape which will eventually cause too much warming.
Device Transforms Greenhouse Gas Into Fuel
Chemists from the University of California, San Diego have developed a device that captures energy from the sun, splits CO2 into CO and oxygen and converts it into fuel. Clifford Kubiak, Professor of chemistry and biochemistry and graduate student Aaron Sathrum explain that the device utilizes a semiconductor and two thin layers of catalysts. It splits carbon dioxide and then generates carbon monoxide and oxygen in a three-step process.
- First, the semiconductor captures the solar energy photons.
- The optical energy is then converted into electrical energy by the semiconductor.
- Finally, the electrical energy is provided to the catalysts.
Searching for Semiconductors
- Finding the right semiconductor has been a challenge for the chemists. They initially used silicone but stated that it was too “wimpy” so have now moved on to using a gallium-phosphide semiconductor. This has twice the band gap of silicone so can absorb more energy from the sun. The silicone semiconductor did not absorb enough energy from the sun and only supplied half of what they needed.
Converting CO into fuel is not a new technology as it was invented in Germany in the 1920’s but since fuel prices have increased; there has been a renewed interest. "The technology to convert carbon monoxide into liquid fuel has been around a long time," Kubiak said. "It was invented in Germany in the 1920s. The United States was very interested in the technology during the 1970s energy crisis, but when the energy crisis ended people lost interest. Now things have come full circle because rising fuel prices make it economically competitive to convert CO into fuel."
- It seems like an attractive option since previous prevention strategies for decreasing green house gases were undesirable to some such as curtailing economic growth.
- There is not necessarily going to be an endless supply of oil, gas or coal so using sustainable sources of energy would be beneficial to both the economy and the environment.
Since this device will recycle green house gas, it is an attractive alternative. While the costs could be initially substantial, money will be saved on transportation and gasoline is not getting any cheaper.
Sources: Science Daily, Device Uses Solar Energy To Convert Carbon Dioxide Into Fuel,2007, NewScientist.com,Tom Simonite,2007,Bionews,2007,Power to the People:The Molecular Revolution in Sustainable Energy,Professor Matthew Davidson,Professor Sailful Islam and Professor Laurie Peter,2006,Scientists Use Solar Energy to Create Liquid Fuel from Carbon Dioxide,Wolfgang Gruener,2007
