Synchrotron Radiation Shed Light to <i>In Situ </i>and Dynamic Observation of High-Temperature Processes

Abstract

The most striking characteristic of observations that use synchrotron radiation is that a material's structural changes can be observed in situ during a specific reaction under conditions closely resembling the actual process or environment of interest, and on a timescale that can resolve fine details of the process (dynamic observation). To make the most of these advantages, we have developed various unique analytical techniques using special reaction cells for in situ and dynamic observation using synchrotron radiation in order to clarify reaction mechanisms of various materials and processes. After reviewing various techniques using synchrotron radiation, recent approaches of quick-XRD (QXRD) and dispersive-XAFS (DXAFS) and their application to sintering reactions in the ironmaking process and reduction-oxidation (redox) reactions in oxide catalysts are discussed in details. The change in atomic structure as well as microstructure could be in situ and dynamically observed with a time-resolution of a few sec. up to 1773 K, revealing the mechanism of formation of CaFe -O oxides form the oxide molten. The change in structure of nano-clusters was successfully observed with a time-resolution of a few m-sec. During redox-gas cycles up to 1223 K, revealing the mechanism of Pd/Sr-Fe-O catalysis for automotive emission control.