Image: Jim West/Alamy Stock Photo
Scientists in Japan have demonstrated a new proof-of-concept reactor that can harvest renewable hydrogen fuel from sunlight and water.
The new 100-square-meters reactor uses photocatalytic sheets to split apart the oxygen and hydrogen atoms found in water molecules, thus siphoning the hydrogen away to be used as fuel.
While the technology remains in its infancy, the scientists behind the research say that, if more efficient photocatalysts can be developed, their breakthrough could enable the production of cheap, sustainable hydrogen fuel to meet various energy needs.
"Sunlight-driven water splitting using photocatalysts is an ideal technology for solar-to-chemical energy conversion and storage, and recent developments in photocatalytic materials and systems raise hopes for its realization," said senior author Kazunari Domen, a chemistry professor at Shinshu University in Japan.
Upon being exposed to light, photocatalysts boost chemical reactions that break water molecules down into their constituent parts. However, most existing "one-step" catalysts – which decompose water into hydrogen and oxygen in one go – are extremely inefficient, leaving most of the hydrogen fuel to be refined using natural gas, a fossil fuel.
To look for a way past this deadlock, the researchers behind the new study investigated a photocatalyst that uses a more sophisticated two-step process, with one step separating out the oxygen and the next step removing the hydrogen.
Creating a photocatalyst for this process enabled the scientists to build their prototype reactor, which ran for three years and worked even better using real sunlight than the ultraviolet light used in the lab.
"Currently, the efficiency under simulated standard sunlight is 1% at best, and it will not reach 5% efficiency under natural sunlight," Domen said.
To make the important strides to increase efficiency, the scientists have called on others to create better photocatalysts and larger reactors. Work on safety will also be vital: Hydrogen fuel refining also produces the explosive byproduct oxyhydrogen, which can be safely disposed of in the two-step process.
Source: Frontiers in Science
Image: Jim West/Alamy Stock Photo