In an attempt to make hydrogen a clean and green fuel source, a new technique has been developed by a University of Colorado Boulder team that uses sunlight to efficiently split the components of water, hydrogen and oxygen. The elaborate process of this technique has been described in the Aug. 2 issue of Science.

According to Gizmag, the solar-thermal system operates by focusing sunlight from a group of mirrors at a single point on top of a tall tower to produce very high temperature. The heat is fed into a reactor containing metal oxides which heats the oxides up and induces them to release oxygen.

The chemical composition of the metal oxide changes to form a new compound that seeks new oxygen atoms. When steam is introduced into the reactor, the compound draws oxygen atoms out of the water molecules, leaving behind hydrogen that can be collected as hydrogen gas.

"We have designed something here that is very different from other methods and frankly something that nobody thought was possible before," said Alan Weimer, a professor and a member of the team that worked on the project. "Splitting water with sunlight is the Holy Grail of a sustainable hydrogen economy."

The team included co-lead authors Weimer and Associate Professor Charles Musgrave, author and doctoral student Christopher Muhich, postdoctoral researcher Janna Martinek, undergraduate Kayla Weston, former CU graduate student Paul Lichty, former CU postdoctoral researcher Xinhua Liang and former CU researcher Brian Evanko.

When compared to other existing methods that can split water into hydrogen and oxygen, Colorado Boulder scientists claim that this is the most proficient method because the two chemical reactions can be conducted at the same temperature.

"The more conventional approaches require the control of both the switching of the temperature in the reactor from a hot to a cool state, and the introduction of steam into the system," said Musgrave. "One of the big innovations in our system is that there is no swing in the temperature. The whole process is driven by either turning a steam valve on or off."

Colorado researchers said that despite their success, the commercialization of such solar-thermal reactor could take several years before becoming a reality.