Pictures show folders swimming in liquid

Nano technology

Technology Innovation Website Editor – 01/08/2022

Illustration and picture (details) of atoms swimming in a liquid.
[Imagem: University of Manchester]

liquid solid interface

Liquids come into contact with solids all the time, creating essential interfaces for everything from life-sustaining biological processes to industrial processes, batteries, fuel cells, and just about anything else we can imagine.

However, we know very little about this fundamental phenomenon.

What we do know is that when a solid surface comes into contact with a liquid, both substances change their composition in response to their proximity to each other – how, how fast, and how each substance behaves remain mysteries to be solved.

“Given the broad industrial and scientific importance of this behavior, it is really surprising how much we still have to learn about the basics of the behavior of atoms on surfaces in contact with liquids. One reason for the lack of so much information is a lack of techniques capable of producing experimental data for solid-liquid interfaces,” explained Professor Sarah Hi from the University of Manchester (UK).

The good news is that Professor Hay’s team has just created a new “nano-dish petri dish”, allowing for the first time observation how individual atoms of a solid behave when that solid comes into contact with a liquid.

This is the liquid cell, which allows the solid-liquid interface to be displayed.
[Imagem: Daniel J. Kelly et al. – 10.1021/acs.nanolett.7b04713]

graphene windows

The team began by stacking layers of a well-studied two-dimensional material, molybdenite. Then they drilled holes in this molybdenum disulfide, covered one side of the graphene, inserted the liquid, and then also covered the other side with graphene – the researchers called this device a “liquid double graphene cell.”

These graphene windows made it possible to create precisely controlled layers of liquid, making it possible for the first time to image individual atoms “swimming” surrounded by the liquid.

By analyzing how the atoms move and comparing the images to the theories, the researchers were able to understand the effect of the fluid on atomic behavior.

They found, for example, that the liquid speeds up the movement of atoms, and also that it changes the atom’s preferred resting places with respect to the underlying solid—which wasn’t quite what the theories had predicted.

Researcher Nick Clarke explained, referring to transmission electron microscopes, a technology that allows us to visualize and analyze individual atoms, but that requires a high vacuum environment — and the structure of materials changes in a vacuum.

green technologies

The team believes cells with transparent windows should have a broad impact on the development of green technologies, such as hydrogen production.

“This is a historic achievement and just the beginning – we are already looking forward to using this technology to support the development of materials for the sustainable chemical processing needed to achieve the world’s zero-emissions goals,” Clark said.

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