Another Photoelectrochemical Catalyst
'An improved, cost-effective catalyst for water-splitting devices
by Staff Writers
Lausanne, Switzerland (SPX) Jan 16, 2014
Publishing in Nature Communications, an EPFL-led team of scientists has found a method to create a high-efficiency, scalable solar water splitting device using cheap materials…
One of the most sustainable methods of producing hydrogen is photoelectrochemical (PEC) water-splitting. Solar energy is used to break water molecules into hydrogen and oxygen through a process called "hydrogen evolution reaction".
This reaction requires a catalyst, which is a chemical agent that increases its speed. In PEC water-splitting devices, a common catalyst used to split water is platinum, which is deposited on the surface of the solar panel's photocathode - the solar panel's electrode that converts light into electric current.
A research team at EPFL has now found a way to make efficient solar-powered water splitting devices using abundant and cheap materials. The group of Xile Hu developed a molybdenum-sulfide catalyst for the hydrogen evolution reaction, and the group of Michael Gratzel developed copper(I) oxide as a photocathode.
The researchers found that the molybdenum sulfide 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.
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.
But more importantly, 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. According to senior author Xile Hu, the work represents a state-of-the-art example for solar hydrogen production devices.'