ReactorAFM/STM - dynamic reactions on surfaces at elevated temperature and atmospheric pressure.

Area of Science:

• Surface Science
• Materials Science
• Catalysis

Background:

• Previous ReactorSTM and ReactorAFM systems allowed studying materials under industrially relevant conditions.
• Advancements in microscopy are crucial for understanding material behavior during chemical reactions.

Purpose of the Study:

• To develop and demonstrate an integrated atomic force microscopy (AFM) and scanning tunneling microscopy (STM) system for in-situ material analysis under reaction conditions.
• To investigate the geometric and electronic structure of materials, specifically catalysts, during chemical processes.

Main Methods:

• Implementation of a qPlus sensor to combine AFM and STM techniques.
• In-situ imaging of a Pd(100) single crystal at 450 K under ultrahigh vacuum and 0.5 bar O2 pressure.
• Characterization of cobalt nanoparticle catalysts on an aluminum oxide support before and after Fischer-Tropsch synthesis.
• Quadrupole mass spectrometry for monitoring reaction products (H2O, ethane, propane, hexane) under 2 bar CO and H2 pressure.

Main Results:

• Combined AFM/STM imaging revealed surface changes on Pd(100) due to oxidation under O2 pressure.
• Cobalt nanoparticle catalysts were imaged before and after reaction, showing structural changes.
• Mass spectrometry confirmed Fischer-Tropsch synthesis by detecting product gases between 490 and 550 K.
• An increase in RMS current was observed on Pd(100) under O2, attributed to oxidation.

Conclusions:

• The developed ReactorAFM/STM system offers a versatile platform for studying catalysts under realistic industrial conditions.
• Combining AFM/STM with mass spectrometry provides comprehensive insights into material structure and reactivity during catalytic processes.
• The system's ability to perform in-situ analysis under reaction conditions is critical for catalyst development and optimization.