MatSciCon2023: Researchers studying graphene have photographed atoms "swimming" in a liquid

To better understand how the presence of liquid alters the behaviour of the solid, a team led by scientists from the National Graphene Institute (NGI) employed stacks of 2D materials like graphene to trap liquid. Their findings were published in the journal Nature.

For the first time, the team was able to photograph a single atom "swimming" in a liquid. The results might have a significant effect on how green technologies like hydrogen production are developed in the future.

When a liquid and a solid are in close proximity to one another, both substances adapt to the other's presence. These atomic-scale interactions at solid-liquid interfaces control the behaviour of fuel cells and batteries used to generate clean power, as well as the effectiveness of systems used to produce clean water and many biological activities.

Professor Sarah Haigh, one of the principal investigators, said: "It is incredibly astounding how much we still don't understand about the principles of how atoms behave on surfaces in contact with liquids given the pervasive industrial and scientific importance of such behaviour. The lack of procedures that can produce experimental data for solid-liquid interfaces is one of the reasons there is a lack of information."

One of the few methods that allows for the observation and analysis of individual atoms is transmission electron microscopy (TEM). The structure of materials changes in a vacuum, and the TEM apparatus needs a high vacuum environment. "In our work, we show that false information is produced if the atomic behaviour is studied in vacuum instead of using our liquid cells," said Dr. Nick Clark, the first author.

Roman Gorbachev, a pioneer in the stacking of 2D materials for electronics, has now developed a "double graphene liquid cell" with the help of the same techniques. Graphene windows encased a 2D layer of molybdenum disulphide that was completely suspended in liquid. They were able to create perfectly regulated liquid layers thanks to their innovative design, which allowed them to record the first-ever movies of individual atoms "swimming" in liquid. 

The researchers were able to comprehend how the liquid affected atomic behaviour by analysing the movements of the atoms in the movies and comparing their findings to theoretical explanations offered by Cambridge University colleagues. It was discovered that the liquid both accelerated the atoms' mobility and altered their preferred resting places.

The researchers investigated a material that holds promise for producing green hydrogen, but the experimental technology they created has a wide range of potential uses. MatSciCon2023

This is a significant accomplishment, but it's just the beginning, according to Dr. Nick Clark. "We are now seeking to apply this technology to promote the development of materials for sustainable chemical processing, which is necessary to meet the global community's net zero objectives," he added.

**Materials provided by University of Manchester. Note: Content may be edited for style and length.**