Tracking single adatoms in liquid in a transmission electron microscope.

Area of Science:

• Materials Science
• Surface Science
• Nanotechnology

Background:

• Single atoms on surfaces are crucial for various chemical and physical processes.
• Transmission electron microscopy (TEM) is key for visualizing single atoms, but liquid imaging faces resolution challenges.
• Graphene liquid cells have improved TEM imaging in liquids, enabling atomic resolution for nanoparticles.

Purpose of the Study:

• To demonstrate atomic-resolution in situ imaging of single adatoms in an aqueous environment.
• To investigate the dynamics and adsorption site preference of platinum adatoms in liquid versus vacuum.
• To develop a novel double graphene liquid cell for advanced TEM studies.

Main Methods:

• Utilized a double graphene liquid cell with a central molybdenum disulfide monolayer and hexagonal boron nitride spacers.
• Performed in situ transmission electron microscopy on platinum adatoms in an aqueous salt solution.
• Analyzed over 70,000 single adatom adsorption sites to compare liquid and vacuum states.

Main Results:

• Achieved atomic resolution imaging of platinum adatoms dynamics in an aqueous solution.
• Observed modified adsorption site distribution for adatoms in liquid compared to vacuum.
• Found significantly higher diffusivities for adatoms in the liquid phase.

Conclusions:

• The double graphene liquid cell enables unprecedented single-atom precision imaging in liquid environments.
• Liquid-phase adatom dynamics differ from vacuum, with altered site preference and increased mobility.
• This technique opens new avenues for studying chemical processes at the single-atom level in situ.