Artificial Leaf May be a Boon to the Renewable Energy Industry

Generating a storing renewable energy, such as solar or wind power, is a key barrier to a clean-energy economy. Now, though, researchers are looking into creating an artificial leaf that could be a major boon to the energy industry.

The new fuel generation system, or artificial leaf, consists of three main components: two electrodes-one photoanode and one photocathode-and a membrane. The photoanode uses sunlight to oxidize water molecules, generating protons and electrons as well as oxygen gas. The photocathode recombines the protons and electrons to form hydrogen gas. A key part of the design is the plastic membrane, which keeps the oxygen and hydrogen gases separate. If the two gases are allowed to mix and are accidentally ignited, an explosion can occur; the membrane lets the hydrogen fuel be separately collected under pressure and safely pushed into a pipeline.

Semiconductors such as silicon or gallium arsenide absorb light efficiently and are therefore used in solar panels. However, these materials also oxidize (or rust) on the surface when exposed to water, so cannot be used to directly generate fuel.

However, a major advance was made that prevented corrosion on the electrodes while still allowing light and electrons to pass through. In addition, inexpensive catalysts for fuel production also helped the development of the new device.

"This new system shatters all of the combined safety, performance and stability records for artificial leaf technology by factor to 5 to 10 or more," said Nate Lewis, one of the researchers, in a news release. "Our work shows that it is indeed possible to produce fuels from sunlight safely and efficiently in an integrated system with inexpensive components. Of course, we still have work to do to extend the lifetime of the system and to develop methods for cost-effectively manufacturing full systems, both of which are in progress."

The findings are published in the journal Energy & Environmental Science.

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