New PEC cell (bottom) developed at Technion. Credit: TechnionNew PEC cell (bottom) developed at Technion. Credit: Technion

New technology developed at the Technion uses solar power to separate hydrogen and oxygen in water. One
potential application is producing hydrogen at the point of sale, such as a gas station where hydrogen-powered electric cars stop to fill up.

Hydrogen as a fuel offers several advantages over other energy sources, including the element’s abundance.
Currently most hydrogen comes from natural gas, but the production process releases carbon dioxide into the atmosphere. Splitting water molecules into hydrogen and oxygen by electrolysis looks feasible. The process uses electricity; electricity production is expensive and causes pollution.

Many researchers are developing photoelectrochemical (PEC) cells that split water molecules directly without using an external power source. The Technion research team addressed the limitations of this method — separate storage for hydrogen and oxygen, collecting the gases from multiple cells, and transporting hydrogen — by developing a new kind of PEC technology.

The new method produces oxygen and hydrogen at different sites. Oxygen is produced exclusively at a large solar farm. Hydrogen is produced elsewhere, at the point of use or purchase. This is accomplished by replacing the electrode in the conventional PEC with a photo- anode. The cells are completely separated. The prototype uses inexpensive nickel hydroxide for electrodes, connected by a metal wire.

Economists at Evonik Creavis GmbH and the Institute of Solar Research at the German Aerospace Center (DLR) calculated that the new technology could offer be appreciable savings over conventional production methods.

Lead researcher Avigail Landman, a graduate student in the Nancy & Stephen Grand Technion Energy Program, won first place in the energy category at the University of Queensland’s Three Minute Thesis competition, held in October 2016.