Developments in in situ Environmental Cell High-Resolution Electron Microscopy and Applications to Catalysis

Abstract

High-resolution in situ controlled-environment electron microscopy (environmental cell TEM (ETEM) or ECELL) instrumentation and techniques, and some of the key applications to dynamic reaction studies in catalysis, are reviewed. Developments over the past decade or so have led to the novel development of ETEM for in situ studies on the atomic scale of operating catalysts under controlled environments. The powerful ETEM technique enables direct access to the important, but often metastable with respect to temperature and gas atmosphere, intermediate phases in dynamic catalysis processes. Unique insights are provided into reaction mechanisms and the sequences of microstructural and nanochemical evolution of catalyst active site structures associated with selectivity and activity, and potential deactivation and poisoning. The examples demonstrate the pivotal role of ETEM in understanding, developing and controlling novel catalysts and processes. The latest developments include wet-ETEM for in situ dynamic studies of liquid--solid reactions in polymerization and molecular electronics applications.