Scientists created a leaf-inspired electrically conductive film that could allow solar devices to split water into hydrogen fuel.
The breakthrough was based off a chemical process seen in plants, California Institute of Technology reported. The film can be applied to semiconducting materials to prevent rust and facilitate a chemical process that is key in the solar-driven production of 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 Nate Lewis, the George L. Argyros Professor and professor of chemistry at Caltech and a co-author of the study.
The innovation could lead to extremely efficient artificial photosynthetic systems, or "artificial leaves." The devices copy the natural process of photosynthesis that plants use to convert sunlight, water, and carbon dioxide into oxygen in the form of carbohydrates.
The artificial leaf is composed of two electrodes (a photoanode and a photocathode) and a membrane. The photoanode is responsible for using sunlight to oxidize water molecules, generating "oxygen gas, protons, and electrons." The photocathode recombines these protons and electrons to create hydrogen gas. The membrane works to keep the two gases separate in order to prevent an explosion, and allows them to be pushed safely into a pipeline.
Scientists have attempted to create similar devices in the past, but previous protective coatings have failed for a number of reasons. This new nickel oxide film exceeds the performance of other protective coatings by a longshot.
"After watching the photoanodes run at record performance without any noticeable degradation for 24 hours, and then 100 hours, and then 500 hours, I knew we had done what scientists had failed to do before," said Ke Sun, a postdoc in Lewis's lab and the first author of the new study.
The findings were published in a recent edition of the Proceedings of the National Academy of Sciences (PNAS).
