Environmental electron microscopy (ETEM) for catalysts with a closed E-cell with carbon windows

In a standard high-resolution electron microscope (Jeol 3010), an environmental sample holder designed by Jeol, has been used for in situ observations at the atomic scale of catalysts, during a chemical reaction. Experiments have been performed in H2 and O2 at a pressure up to 4 mbar at room temperature, and in the case of H2, at various temperatures until 350 °C. For the first time, Au and Pd clusters supported on TiO2 and amorphous carbon have been observed with a windows—cell environmental electron microscopy (ETEM) system, with the resolution of the (1 1 1) lattice fringes. Au clusters have been cleaned in H2 and have got the equilibrium shape of the fcc crystals during annealing. The same Au particles can be observed during successive treatments under O2 and H2. For Pd clusters in situ exposed to O2 , the adhesion has decreased.