New catalyst makes hydrogen harvesting more economical

Thursday, 16 February 2017
A schematic diagram of Ru@C₂N with ruthenium shown in gold, carbon in grey, and nitrogen in turquoise. Image: UNIST

A team of Korean engineers has developed a new ruthenium-based catalyst that can split water into hydrogen almost as well as platinum, but is less costly and more available.

The ideal catalyst should exhibit high hydrogen conversion efficiency, excellent durability, operate well under low-voltage, and be economical.

Platinum-based catalysts suffer from being expensive and less stable in an alkaline environment so the researchers from the Ulsan National Institute of Science and Technology (UNIST) have been looking for cheaper alternatives.

They synthesised ruthenium and C₂N, a two-dimensional organic structure, into a catalyst they call Ru@C₂N. The process involved mixing ruthenium salt (RuCl₃) with the monomers which forms the porous two-dimensional organic structure, C₂N. The Ru@C₂N catalyst is then produced after going through reduction and heat treatment processes.

The researchers used the same process to build M@C₂N where M is cobalt, nickel, lead and platinum. When comparing their efficiency of hydrogen production, the Ru@C₂N catalyst exhibited the highest catalytic performance at the lowest overvoltage, as well as superior catalytic activity.

The catalyst satisfies all four commercial competitiveness requirements of water-splitting catalysts. It exhibits turnover frequency as high as platinum and can be operated on low-voltage supply. In addition, it is not affected by the pH of the water and can be used in any environment.

“Our study not only suggests new directions in materials science, but also presents a wide range of possibilities from basic to applied science,” says team leader Professor Jong-Beom Baek of the Department of Energy and Chemical Engineering at UNIST.

“This material is expected to attract attention in many areas thanks to its scientific potential.”

The research was published in the journal Nature Nanotechnology.

[A schematic diagram of Ru@C₂N with ruthenium shown in gold, carbon in grey, and nitrogen in turquoise. Image: UNIST]

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