Harvesting hydrogen fuel from sunlight and water at lower cost

October 2, 2014

Electrodes separate hydrogen from water (credit: Alain Herzog)

Swiss researchers have created a method of producing hydrogen fuel from sunlight and water at 12.3 percent conversion efficiency, a record using earth-­abundant materials instead of expensive rare metals.

The EPFL researchers used a pair of solar cells made with a mineral called perovskite and low-cost electrodes to create an electrolyzer that separates the water molecules.

The high efficiency is based on a characteristic of perovskite cells: their ability to generate an open circuit voltage greater than 1 V (silicon cells stop at 0.7 V). A voltage of 1.7 V or more is required for water electrolysis to occur.

Hydrogen can be used in a fuel cell to generate electricity.

The work was published in the journal Science.