Cost-Effective Water Electrolysis

Water electrolysis is an effective way to produce hydrogen and oxygen by breaking the water molecule in two parts. Since the 19th century, scientist knows how interesting it would be to master this electrolysis process. At this time, the famous French author Jules Verne wrote: “I believe that water will one day be employed as fuel, that hydrogen and oxygen which constitute it, used singly or together, will furnish an inexhaustible source of heat and light, of an intensity of which coal is not capable.”

This quest for using water as a potential source of energy is still ongoing. Hydrogen stores a tremendous amount of energy and so offers great potential as a sustainable, carbon-free source of power. Noble metals, such as iridium and ruthenium, have excellent oxygen-evolution performance, but are very expensive. A viable solution could be fine with low-cost alkaline water electrolysis. In fact, it seems to be a sustainable approach to producing hydrogen using renewable energy inputs. However, preventing hydrogen/oxygen mixing and efficiently using the unstable renewable energy are very challenging.

Recently a team of researchers from King Abdullah University of Science and Technology has made interesting progress. Using nickel hydroxide, they managed to decouple the hydrogen and oxygen production in alkaline water electrolysis, which overcomes the gas-mixing issue and may increase the use of renewable energy. Their technique to create a material for cost-effective water electrolysis was to use a simple chemical method for preparing nickel-based anodes improving the oxygen-evolution reaction.

In this architecture, the hydrogen production occurs at the cathode by water reduction, and the anodic Ni(OH)2 is simultaneously oxidized into NiOOH. This new architecture brings a potential solution to facilitate renewables-to-hydrogen conversion. The presented results showed nickel-based electrocatalysts have encouraging performance. Notable amongst these is nickel-iron oxide; but the cost and complexity of its synthesis is a drawback.

“Existing electrolyzers function in extremely alkaline or acidic environments, and these harsh conditions will be costly when driven by renewable energy sources.[…] Also important is that most studies on electrocatalytic water splitting have been performed at room temperature. Higher temperatures are required in practical systems.” – Tatsuya Shinagawa, King Abdullah University of Science and Technology

The team showed that their electrode exhibited greatly superior oxygen-evolution reaction performance compared to nickel-iron oxide under near neutral pH conditions and at temperatures commonly used in industrial processing.

Continue reading at: https://phys.org/news/2017-07-nickel.html