Background to in situ ETEM

Before discussing novel in situ ETEM developments for heterogeneous catalysis, we present some background information about various in situ developments in the materials sciences. A number of notable in situ experiments have relied upon modifications to the standard TEM operations. The main electron optical functions of the TEM, especially the electron gun, depend on a high vacuum environment. The typical 10 -10 mbar TEM environment is mildly reducing. With an ECELL, controlled chemically reducing atmospheres, such as 

hydrocarbons, CO and oxidizing atmospheres (such as O2) or solvent-rich (He/water vapour) are used. A wide range of gases and vapours can be used. 

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