The first pictures of individual atoms “swim” in the liquid

In a publication in Nature, the team led by National Graphene Institute (NGI) researchers used dozens of two-dimensional materials such as graphene to trap liquid in order to better understand how the presence of liquid alters the behavior of a solid.

The team was able to capture images of individual atoms “swim” in liquid for the first time. The findings could have a wide-ranging impact on the future development of green technologies such as hydrogen production.

When a solid surface comes into contact with a liquid, both substances change their composition in response to the proximity of the other. Atomic-scale interactions at solid-liquid interfaces control the behavior of batteries and fuel cells to generate clean electricity, as well as determine the efficiency of clean water generation and support many biological processes.

One of the reasons for the lack of information is the lack of techniques capable of producing experimental data for solid-liquid interfaces.”

Transmission electron microscopy (TEM) is one of the few techniques that allows viewing and analyzing individual atoms. However, the TEM instrument requires a high vacuum environment and the material structure changes in vacuum. “In our work, we show that disinformation is provided if atomic behavior is studied in a vacuum rather than using liquid cells,” explained first author Dr. Nick Clark.

Professor Roman Gorbachev pioneered stacking of 2D materials for electronics, but here his group used the same techniques to develop a ‘liquid double graphene cell’. A two-dimensional layer of molybdenum disulfide was completely suspended in a liquid and coated with graphene windows. This new design allowed them to provide precisely controlled layers of the liquid, allowing for unprecedented video capture showing individual atoms “swimming”, surrounded by liquid.

By analyzing how the atoms move in the videos and comparing them with theoretical insights provided by colleagues at the University of Cambridge, the researchers were able to understand the effect of the fluid on atomic behavior. The liquid is found to accelerate the movement of atoms as well as change preferred rest locations relative to the basic solid.

The team studied a material promising to produce green hydrogen, but the experimental technology they developed could be used in many different applications.

Dr Nick Clark said: “This is a historic achievement and only the beginning: We are already looking forward to using this technology to support the development of materials for sustainable chemical processing, which is essential to achieving the world’s zero-zero ambitions.”