4:00 PM - 4:15 PM
[MIS18-06] Transmission Electron Microscopic Observation of Clathrate Hydrates being Formed from Ice in High-Pressure Environments
Keywords:Clathrate hydrate, Transmission electron microscopy, Ice, Environmental cell, High-pressure environments
Clathrate hydrates are crystals that form a cage-like structure of water molecules and incorporate a free molecule into the cage. Their formation temperature and pressure vary depending on the type of molecules incorporated into the cage, but the environment is basically low temperature and high pressure. In particular, gas hydrates, which are clathrate hydrates that incorporate gas molecules, have potential applications in a variety of fields, such as energy storage and gas separation [1]. The conditions for the formation of clathrate hydrates were applied to the environments in space, suggesting the presence of them in icy bodies in the solar system [2]. Thus, clathrate hydrate has the potential to exist in the universe, where water and gas molecules are present and under appropriate temperature and pressure conditions. For such applications and discussions, it is important to clarify the fundamental properties of clathrate hydrates, such as their formation environment, morphology, and formation kinetics.
Recently, an observation system that can cool an environmental cell by Peltier devices was developed for transmission electron microscopy [3]. The environmental cell can isolate a volatile sample from a high vacuum environment by sandwiching it between two thin electron-transparent membranes. Observations of ice crystallization from water have been achieved with this system [3]. During observation of ices the system, we discovered that crystals with clathrate hydrate structure were forming. Here we will report on the results of analysis of the crystals and discuss their formation process inside the environmental cell. This method has the potential to enable in situ observation of the formation of clathrate hydrates from ice in nanoscale and is expected to be a new approach for studying clathrate hydrate [4].
[1] A. Hassanpouryouzband et al. Chem. Soc. Rev. 49, (2021) 5225.
[2] W. L. Mao et al., Science 297 (2002) 2247.
[3] T. Yamazaki & Y. Kimura, Microsc. Microanal. 29 (2023) 1940.
[4] This work was supported by JSPS KAKENHI Grant Numbers JP20H05657 and JP21K18901.
Recently, an observation system that can cool an environmental cell by Peltier devices was developed for transmission electron microscopy [3]. The environmental cell can isolate a volatile sample from a high vacuum environment by sandwiching it between two thin electron-transparent membranes. Observations of ice crystallization from water have been achieved with this system [3]. During observation of ices the system, we discovered that crystals with clathrate hydrate structure were forming. Here we will report on the results of analysis of the crystals and discuss their formation process inside the environmental cell. This method has the potential to enable in situ observation of the formation of clathrate hydrates from ice in nanoscale and is expected to be a new approach for studying clathrate hydrate [4].
[1] A. Hassanpouryouzband et al. Chem. Soc. Rev. 49, (2021) 5225.
[2] W. L. Mao et al., Science 297 (2002) 2247.
[3] T. Yamazaki & Y. Kimura, Microsc. Microanal. 29 (2023) 1940.
[4] This work was supported by JSPS KAKENHI Grant Numbers JP20H05657 and JP21K18901.