Using solar energy to convert CO2 to fuel proves to be 10 times more efficient than natural photosynthesis

Under a program funded by the US Department of Energy, a team of researchers has found that it is possible to achieve a ten-fold increase in efficiency over natural photosynthesis when it comes to converting carbon dioxide with solar energy.

Being able to convert carbon dioxide to carbon monoxide and a blend of hydrogen not only provides cleaner fuel, it also means less carbon dioxide in the atmosphere. The technique to do this is similar to natural photosynthesis; however, the Mother Nature approach yields an efficiency range of just 0.5 to 2%. Current technology can get that range up to 7%, but researchers at Lawrence Berkeley National Laboratory, working at the Joint Center for Artificial Photosynthesis, have proven it can be even higher. 

In their latest work, the team looked at four types of artificial photosynthesis techniques — three rely on photoelectric cells (with different numbers of p-n junctions), while the other uses a photovoltaic electrolyzer (a system where the photovoltaic component lies out the reaction chamber). Additionally, they looked at using copper or silver cathodes in the reactions. 

They report that two configurations are most ideal — one can produce a synthetic gas at 18.3%, and the other could produce hythane at around 20.3% efficiency (worth noting — hythane produces significantly less emissions when burned than either natural gas or diesel).

The team believes any technology that comes from their research will likely be used as part of a large solar complex for the purpose of offering a way to store excess energy in a way that doesn’t involve batteries. Admittedly, they do not know of any specific device that could be used to pull the carbon dioxide directly from the air, but noted that it might be best to start out using a current source, like the gas generated from a natural gas well. 

To learn more, read the team’s full report, entitled Thermodynamic and achievable efficiencies for solar-driven electrochemical reduction of carbon dioxide to transportation fuels, which was published in Proceedings of the National Academy of Sciences.

Via: techXplore.com