Radiation Chemistry in Environmental Transmission Electron Microscopy

Area of Science:

• Materials Science
• Chemistry
• Physics

Background:

• Environmental transmission electron microscopy (E-TEM) allows direct nanoscale observation of chemical processes.
• Radiolysis, molecule dissociation by electron beams, significantly impacts reaction pathways.
• The effect of radiolysis in gas-phase E-TEM is largely unexplored.

Purpose of the Study:

• To develop a numerical model for radiation chemistry in gas and liquid E-TEM environments.
• To investigate the impact of radiolysis on gas-phase reactions in E-TEM.
• To provide guidelines for controlling radiolysis in closed-cell nanoreactors.

Main Methods:

• Numerical modeling of radiation chemistry in gas and liquid E-TEM.
• Validation through case studies: aluminum nanocube oxidation and carbon monoxide disproportionation.
• Analysis of radiolytic species reactivity and accumulation at varying pressures.

Main Results:

• Gas-phase E-TEM generates less reactive radiolytic species than liquid-phase systems.
• These species can reach reaction-altering concentrations, especially at elevated pressures.
• Increased electron beam dose rates accelerate reaction kinetics, as seen in AlOx growth and carbon deposition.

Conclusions:

• Radiolysis is a critical factor in gas-phase E-TEM, even with less reactive species.
• Understanding and controlling radiolysis is essential for accurate nanoscale observations.
• This research enables rational materials design with sub-Ångstrom resolution using E-TEM.