Controlled environment specimen transfer.

Area of Science:

• Materials Science
• Catalysis Science
• Analytical Chemistry

Background:

• Materials sensitive to ambient conditions require controlled environments for in situ characterization.
• Successive complementary analyses necessitate maintaining specimen integrity during transfer.

Purpose of the Study:

• To introduce and validate an in situ transfer concept for linking environmental transmission electron microscopy (ETEM) and in situ X-ray diffractometry (XRD).
• To demonstrate the capability of a specialized transfer holder for maintaining controlled gaseous environments at elevated temperatures during specimen transfer.

Main Methods:

• Development of a dedicated transmission electron microscope specimen transfer holder enabling sealed transfer under controlled gas composition, temperature, and pressure.
• Investigation of Cu/ZnO/Al2O3 (methanol synthesis) and Co/Al2O3 (Fischer-Tropsch synthesis) catalyst systems sensitive to air oxidation.
• Sequential in situ XRD and ETEM analyses of catalysts, including reduction steps performed in either instrument.

Main Results:

• The transfer holder successfully maintained a reactive environment, preventing oxidation of sensitive catalyst materials during transfer between instruments.
• Cu/ZnO/Al2O3 catalyst was reduced via in situ XRD and transferred to ETEM for local-scale analysis without state change.
• Co/Al2O3 catalyst was reduced in ETEM and maintained its reduced state outside the microscope in a reactive environment.

Conclusions:

• The developed in situ transfer holder effectively facilitates complementary in situ experiments on the same specimen.
• This method preserves the specimen's state during transfer, crucial for accurate characterization of air-sensitive catalysts.
• The approach enables advanced correlative microscopy and diffraction studies of catalytic materials under relevant process conditions.