Making metal atoms behave – one layer at a time

A new method using argon to create tiny traps on carbon surfaces allows metals to form stable, ultra-thin layers, unlocking new, efficient possibilities for clean energy and electronics. 

Recent research conducted at ePSIC has tackled a major challenge in materials science: how to make ultra-thin layers of metal stick to surfaces in a stable and useful way.  

Dr Emerson Kohlrausch demonstrating how atoms are guided and bonded to precise locations on a carbon surface. Nottingham University

These ultra-thin metal layers, which are called single-layer metal clusters (SLMCs), consist of just one to a few atoms and are highly valuable for sustainable technologies like energy storage and catalysis. Unlike traditional three-dimensional metal clusters or nanoparticles, SLMCs expose all their atoms to the surrounding environment, making them more efficient and tunable for chemical reactions and energy applications. 

However, making the clusters is challenging as they are naturally unstable. Metal atoms tend to clump together which wastes materials and reduces the performance. In an effort to increase stability, scientists can add other elements, like nitrogen, fluorine, or phosphorus, to the carbon surface, to stop the clumping.  

The new breakthrough, published in Advanced Science, was made by researchers at Nottingham University and Birmingham University, using Diamond’s ePSIC and SuperSTEM. The team found a universal method to keep the metal atoms spread out in a single layer. They blasted argon plasma at a carbon surface to create empty spots called vacancies – where the carbon atoms were basically knocked out by argon ions. 

These engineered defects are like “sticky spots” that trap and hold the metal atoms in place, creating a stable single layer. The key is to do this in a clean, air-free environment. If the surface is exposed to air, the vacancies get clogged and stop working.  

The researchers found that this method works for 21 different metals, including alloys, and doesn’t require any additional chemicals or treatments. Moreover, this method resulted in record-breaking density, with the highest number of metal atoms per area ever recorded – up to 4.3 atoms per square nanometre. These metal layers stayed intact and stable even after heating and 16 months of air exposure.  

This amazing discovery could lead to more efficient and cheaper catalysts for clean energy, as well as better materials for electronics and sensors. The discover offers a universal, scalable way to make advanced materials without complex chemistry.