New instrumentation and techniques to monitor chemical surface reactions on single crystals over a wide pressure range (10−8–105 Torr) in the same apparatus

Abstract

The development of an apparatus to monitor catalytic reactions on small surface area samples (∠1 cm²) over a wide pressure range [10⁻⁸–10⁵ Torr (∠10⁻⁶–10⁷Pa)] is discussed. Previous experience with catalysis in the low pressure range (10⁻⁸–10⁻⁴ Torr) has resulted in the development of a high pressure isolation cell to monitor reactions in the range 0.1–100 atm. The apparatus incorporates all of the surface analysis features (LEED, AES, and mass spectrometry) and permits UHV analysis of the catalyst surface before and after reaction without removing the sample from the chamber. The importance of obtaining data under reaction conditions appropriate to the equivalent industrial process is emphasized.