New artificial leaf turns sunlight into hydrogen fuel

A team of researchers from Germany and South Korea have developed a new, more efficient artificial leaf, capable of turning sunlight into hydrogen fuel.

The leaf’s design replicates the process of underwater photosynthesis used by aquatic plants, splitting water into hydrogen and oxygen. Sunlight is harvested by dual photoelectrodes in which a pair of photoanodes absorb solar energy.

The free electrons, excited by the sun’s rays, are carried through a semiconductor and used to catalyze a water-splitting chemical reaction. The end result is cheap and stable hydrogen fuel, which can be burned without contributing CO2 emissions.

Scientists believe hydrogen fuel is key to a reduction in global carbon emissions.

The new leaf and its dual photoanodes are designed to absorb only specific wavelengths of light — a specific bandgap for each anode — just as aquatic plants focus their efforts on capturing the energy of only the spectral wavelengths that penetrate through the water.

The device currently boasts a water splitting efficiency of 7.7 percent, still short of the threshold for a commercially viable solar-hydrogen production.

“We aim to achieve 10 percent enhanced light harvesting efficiency within three years,” Jae Sung Lee, a chemical engineer at the Ulsan National Institute of Science and Technology, said in a news release. “This technology will greatly contribute to the establishment of the renewable-energy-type hydrogen refueling station by supplying cheap fuel for hydrogen fuel cell vehicles.”

Researchers detailed their new fuel-producing leaf in the journal Nature Communications.

UPI