Scientists reveal the first images of atoms “floating” in a liquid

The movement of single atoms through a liquid has been captured on camera for the first time.

Using a sandwich of materials so thin they are effectively two-dimensional, the scientists trapped and watched platinum atoms “float” on the surface under various pressures.

The results will help us better understand how the presence of a liquid changes the behavior of a solid with which it is in contact – which in turn has implications that could affect the development of new substances and materials.

“Given the widespread industrial and scientific importance of such behavior, it is truly surprising how much we have to learn about the fundamentals of the behavior of atoms on surfaces in contact with liquids,” explained materials scientist Sarah Hay of the University of Manchester in the UK. .

“One reason the information is lacking is the lack of techniques that can provide experimental data for solid-liquid interfaces.”

When a solid and a liquid are in contact with each other, the behavior of the two materials changes where they meet. These interactions are important for understanding a wide range of processes and applications, such as the transport of materials in our own bodies or the movement of ions in batteries.

The researchers note that it is extremely difficult to view the world on an atomic scale. Transmission electron microscopy (TEM), which uses a beam of electrons to generate an image, is one of the few techniques available.

However, obtaining reliable data on the behavior of atoms in this way is difficult. Previous work in graphene liquid cells has been promising but yielded conflicting results. In addition, TEM typically requires a high vacuum environment to operate. This is a problem because many materials do not behave the same under different pressure conditions.

Fortunately, a form of TEM has been developed to work in liquid and gaseous media, which the team uses for their research.

The next step was to create a special set of microscopic “slides” to contain the atoms. Graphene is the ideal material for these experiments because it is two-dimensional, strong, inert and impermeable. Building on previous work, the team developed a double graphene liquid cell capable of working with existing TEM technology.

This cell was filled with a precisely controlled saltwater solution containing platinum atoms, which the team watched move on a solid surface of molybdenum disulfide.

The images revealed some fascinating insights. For example, atoms move faster in a liquid than outside it, and choose different places on the solid surface to rest.

In addition, the results inside and outside the vacuum chamber are different, suggesting that changes in ambient pressure can affect the behavior of the atoms. Moreover, the results of experiments obtained in vacuum chambers will not necessarily be indicative of this behavior in the real world.

“In our work, we show that misleading information is provided if atomic behavior is studied in a vacuum instead of using our liquid cells,” said materials engineer Nick Clarke of the University of Manchester.

“This is an important achievement and is just the beginning – we are already looking to use this technique to help develop materials for the sustainable chemical processing needed to achieve net zero ambitions.”

The material the team investigated is relevant to the production of green hydrogen, but both their techniques and the results they obtained have much broader implications, the researchers said.

The article was published in Nature.

Leave a Comment