Applications of In-Situ Electron Microscopy in Catalysis

Abstract

Controlled reduction and oxidation reaction experiments on metal oxide catalysts, sulphides, and iron-titanium oxide minerals have been conducted in an environmental (or gas reaction) cell fitted to an AEI-EM7 high voltage electron microscope operating at 1MV. With this technique it is possible to observe dynamic heterogeneous reactions using gas pressures in the range from a few torr to an atmosphere, and temperatures from room temp, to ∼1000°C. A full dynamic description of the behaviour of the solid with respect to temperature, pressure, gaseous environments can therefore be obtained. These observations are useful in understanding mechanisms of heterogeneous catalysis, redox processes, and migration of the reduced species, which affect catalyst selectivity and activity. Examples of some in-situ reactions have been reported in the literature.