Probing dynamics of nanostructures under reaction conditions using insitu TEM
In-situ transmission electron microscopy (TEM) is an area of research, where materials dynamic processes under heat, gas environment, mechanical stress, and electric/magnetic field are characterized using a transmission electron microscope.
Among various in-situ experiments, the VORTEX group mostly focuses on in-situ gas-solid reaction experiments. Therefore, we are equipped with the state-of-art instruments for in-situ gas TEM experiments as shown in figure.
FEI Titan Environmental TEM (ETEM) with a differentially pumped environmental cell allows to feed gases up to 200 Torr and this open cell geometry enables atomic resolution imaging under gas environments. In addition, our electrically-controlled gas manifold system has been installed to introduce stable gas stream into ETEM and this significantly reduces gas induced sample drift. Also, a MEMS device based heating stage enables drift-free high resolution imaging.
The sophisticated in-situ TEM instrumentation in the VORTEX group enables direct observation of thermal behavior of materials under applied heat and gases. The in-situ capability is highly useful in heterogeneous catalysts research.
Specifically, it can directly be used to probe sintering mechanisms of catalyst nanoparticles at high temperature and gas environment. In-situ HAADF-STEM video collected at 500 degree C shows the “migration and coalescence” type sintering of Au nanoparticles on support.