A new approach creates an exceptional single-atom catalyst for water splitting

Anchoring individual iridium atoms on the surface of a catalytic particle boosted its performance in carrying out a reaction that’s been a bottleneck for sustainable energy production.

A new way of anchoring individual iridium atoms to the surface of a catalyst increased its efficiency in splitting water molecules to record levels, scientists from the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University reported today.

It was the first time this approach had been applied to the oxygen evolution reaction, or OER ­–part of a process called electrolysis that uses electricity to split water into hydrogen and oxygen. If powered by renewable energy sources, electrolysis could produce fuels and chemical feedstocks more sustainably and reduce the use of fossil fuels. But the sluggish pace of OER has been a bottleneck to improving its efficiency so it can compete in the open market.

The results of this study could ease the bottleneck and open new avenues to observing and understanding how these single-atom catalytic centers operate under realistic working conditions, the research team said.

They published their results today in the Proceedings of the National Academy of Sciences.

Read more on the SLAC website

Image: An illustration depicts a new system developed at SLAC and Stanford that anchors individual iridium atoms to the surface of a catalyst, increasing its efficiency at splitting water to record levels. The eight-sided support structures, shaded in blue, each contain a single iridium atom (large blue spheres). The iridium atoms grab passing water molecules (floating above and to the left of them), and encourage them to react with each other, releasing oxygen molecules (above and to the right). This reaction, known as the oxygen evolution reaction or OER, plays a key role in producing sustainable fuels and chemicals.

Credit: Greg Stewart/SLAC National Accelerator Laboratory

A 1-Atom-Deep Look at a Water-Splitting Catalyst

X-ray experiments at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) revealed an unexpected transformation in a single atomic layer of a material that contributed to a doubling in the speed of a chemical reaction – the splitting of water into hydrogen and oxygen gases. This process is a first step in producing hydrogen fuel for applications such as electric vehicles powered by hydrogen fuel cells.

The research team, led by scientists at SLAC National Accelerator Laboratory, performed a unique X-ray technique and related analyses, pioneered at Berkeley Lab’s Advanced Light Source (ALS), to home in on the changes at the surface layer of the material. The ALS produces X-rays and other forms of intense light to carry out simultaneous experiments at dozens of beamlines.

Read more on the LBL website

Image: This illustration shows two possible types of surface layers for a catalyst that performs the water-splitting reaction, the first step in making hydrogen fuel: The gray surface is lanthanum oxide and the colorful surface is nickel oxide. A rearrangement of nickel oxide’s atoms while carrying out the reaction made it twice as efficient. Researchers hope to harness this phenomenon to make better catalysts. Lanthanum atoms are depicted in green, nickel atoms in blue, and oxygen atoms in red.

Credit: CUBE3D