For years, solar fuel research has focused on the development of catalysts that can separate water into hydrogen and oxygen using only sunlight. The resulting hydrogen fuel could be used to power motor vehicles, power plants and fuel cells. As the only thing that occurs when burning hydrogen is water, no carbon pollution is added to the atmosphere.
In 2014, researchers in Harry Gray’s laboratory, Professor of Chemistry Arnold O. Beckman of Caltech, developed a water splitting catalyst made of nickel and iron layers. However, no one was completely sure how it worked. Many researchers hypothesized that the nickel layers, and not the iron atoms, were responsible for the water-splitting capacity of the catalyst (and others like it).