Photosynthesis is the process used by plants, algae and certain bacteria to harness energy from sunlight and turn it into chemical energy. It is often described as the green engine of life on earth.
For quite some time, there have been extensive research efforts around the world in the area of artificial photosynthesis. The goal is to somehow mimic the behavior of plants in order to generate clean-burning fuels using nothing more than sunlight and the carbon dioxide in the air.
Researchers at the University of Cambridge have recently demonstrated a so-called artificial leaf that can directly produce syngas using sunlight. Syngas is a fuel gas mixture consisting primarily of hydrogen and carbon monoxide. Most people haven’t heard of syngas, but many products are created using it. Being able to produce it sustainably would be a critical step to a far greener chemical and fuel industry.
The artificial leaf contains two light absorbers, similar to the molecules in plants that harvest sunlight, which are combined with a catalyst made from the naturally abundant element cobalt. When the device is immersed in water, one light absorber uses the catalyst to produce oxygen. The other carries out the chemical reaction that reduces carbon dioxide and water into carbon monoxide and hydrogen. The result is the syngas mixture.
It turns out that even a rainy or overcast day provides enough light to drive the process.
Previous artificial leaf devices have mostly just produced hydrogen. The Cambridge device produces syngas thanks to the novel combination of materials and catalysts it uses.
The researchers are now focused on finding ways to use the technology to produce a sustainable gasoline substitute.
**********
Web Links
‘Artificial leaf’ successfully produces clean gas
Photo, posted August 15, 2014, courtesy of Mike Mozart via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio.
