First observation of dynamic shape changes of a gold nanoparticle catalyst under reaction gas environment by transmission electron microscopy

The surface structure of catalytic gold nanoparticles was observed dynamically during CO oxidation using an environmental‐cell transmission electron microscope (E‐cell TEM) system. In the developed system, the gold catalyst specimen can be set under the reaction gas condition by separating it from the vacuum using ultra‐thin carbon films. We have developed a method capable of yielding for carbon films 8‐nm thick, capable of withstanding a gas pressure of 2 atm. In situ observations using the above system indicated marked changes in the surface shape of the gold nanoparticle catalyst during the reaction.