Researchers have demonstrated that by using argon plasma, metal atoms can be dispersed and guided to desired positions. This new strategy ensures that not a single atom goes to waste and maximises the use of rare and precious metals.
In a study published in Advanced Science, researchers from the University of Nottingham, the University of Birmingham, Diamond Light Source, and the EPSRC SuperSTEM demonstrate how using fast argon ions to engineer defects on carbon surfaces allows metal atoms to bind and self-assemble into ultra-thin, single-layer metal clusters, forming unusual 2D metal islands of sub-nanometre size.
Industry uses metals for catalysis, but some of these metals are precious and rare, utilising metals with maximum efficiency is vital to ensure a sustainable future. Green technologies, such as hydrogen production, are advancing very fast, but they put pressure on the limited supply of critical elements and create environmental crises on the planet.
Every atom counts. Precious and rare metals are vital for clean energy and industrial catalysis, but their supply is limited. We've developed a scalable strategy to ensure not a single atom goes to waste.
Unlike conventional approaches that require element-specific conditions or chemical dopants, the team's method exploits atomic 'vacancies', tiny holes created by argon ion bombardment on a carbon surface, as universal binding sites. These defect sites act as atomic traps that strongly anchor metal atoms, preventing them from forming larger and less efficient 3D nanoparticles.
Remarkably, the method proved effective across 21 different elements, including notoriously difficult-to-control metals such as silver and gold. "This is a one-size-fits-all solution," says Professor Andrei Khlobystov. "We can create mono-, bi-, or even tri-metallic atomic layers, with each atom precisely where we want it. That level of control is unprecedented."
What makes this method so remarkable is its simplicity. Rather than relying on complicated chemical reactions, it utilises the physical movement of atoms from one place to another, significantly reducing the number of variables involved. Therefore, we can accurately recreate the formation of these materials in computer simulations, which will guide further development of the new method.
The innovation lies not just in trapping atoms, but in doing so under pristine, solvent- and air-free conditions that prevent site passivation. "What makes this so powerful, yet so difficult, is that we create highly reactive sites on the surface and release metal atoms under tightly controlled conditions. At that stage, both the atoms and the surface are extremely unstable and reactive. Even a slight loss of control can lead to an incorrect metal configuration, but with the right conditions, atoms lock into place permanently. It's like catching lightning in a bottle, just at the atomic scale," Dr Kohlrausch explains.
Applications of these single-layer metal clusters (SLMCs) range from more efficient hydrogen production and ammonia synthesis to CO₂ conversion and energy storage. The researchers achieved record areal densities of up to 4.3 atoms per nm² and proved stability in air for over 16 months, as well as in catalytic environments.
"We're making 2D metal catalyst on any surface a reality," says Dr Jesum Alves Fernandes, the project leader. "Our vision is to design materials where every single atom is active and working, and nothing is wasted. This is how we make catalysis truly green."
