Hydrogen production and storage in scalable solar cell

Scientists in Switzerland have developed a method to create a highly-efficient, scalable solar water splitting device using inexpensive materials.

Solar power systems cannot consistently produce adequate energy due to intermittency but a solution to this problem is a device that can store energy in the form of hydrogen.

One of the most sustainable methods of producing hydrogen is photoelectrochemical (PEC) water-splitting, a process where solar energy is used to break water molecules into hydrogen and oxygen through a process called hydrogen evolution reaction.

This reaction requires a catalyst and in PEC water-splitting devices platinum is commonly used for the job: it is deposited on the surface of the solar panel’s photocathode, which is the solar panel’s electrode that converts light into electric current.

A research team at EPFL in Switzerland has now found a way to make efficient solar-powered water splitting devices using abundant and cheap materials.

According to EPFL, the group of Xile Hu developed a molybdenum-sulphide catalyst for the hydrogen evolution reaction, and the group of Michael Grätzel developed copper(I) oxide as a photocathode.

The researchers found that the molybdenum sulphide can be deposited on the copper(I) oxide photocathode for use in PEC water splitting through a simple deposition process that can be easily expanded onto a large scale.

In a statement EPFL said the technique shows comparable efficiency to other hydrogen evolution reaction catalysts like platinum, it preserves the optical transparency for the light-harvesting surface and it shows improved stability under acidic conditions, which could translate into lower maintenance.

Both the catalyst and the photocathode are made with cheap, earth-abundant materials that could greatly reduce the cost of PEC water-splitting devices in the future.

Details of the research have been published in Nature Communications.