A study recently published in the journal Proceedings of the National Academy of Sciences reveals the development of an electrically conductive film that could help devices capable of using sunlight to split water into hydrogen fuel.
“We have developed a new type of protective coating that enables a key process in the solar-driven production of fuels to be performed with record efficiency, stability and effectiveness, and in a system that is intrinsically safe and does not produce explosive mixtures of hydrogen and oxygen,” said co-author Nathan Lewis of the California Institute of Technology (Caltech), in a recent statement.
According to Caltech, the development could lead to efficient artificial photosynthetic systems – also known as solar-fuel generators or “artificial leaves” — that can convert sunlight, water, and carbon dioxide into oxygen and fuels in the form of carbohydrates.
The team’s artificial leaf consists of two electrodes – a photoanode and a photocathode – and a membrane. The photoanode utilizes sunlight to generate oxygen gas, protons, and electrons, and the photocathode uses those protons and electrons to form hydrogen gas. The membrane keeps the two gases separate to eliminate the chance of explosion. Researchers experimented with the development of protective coatings for these electrodes.
“You want the coating to be many things: chemically compatible with the semiconductor it’s trying to protect, impermeable to water, electrically conductive, highly transparent to incoming light and highly catalytic for the reaction to make oxygen and fuels,” said Lewis. “Creating a protective layer that displayed any one of these attributes would be a significant leap forward, but what we’ve now discovered is a material that can do all of these things at once.”
While the new development is crucial to the production of a commercial product that can convert sunlight into fuel, there are still many steps in the system that need to be perfected, such as the photocathode.
“Our team is also working on a photocathode,” said Lewis. “What we have to do is combine both of these elements together and show that the entire system works. That will not be easy, but we now have one of the missing key pieces that has eluded the field for the past half-century.”