ABSTRACT
The aim of this work was to study the effects of Pd/SnO2 reduction using HRTEM. For this purpose, we submitted SnO2 samples impregnated with Pd to both in-situ and ex-situ reduction treatments. The ex-situ reduction treatments consisted of heating the sample under Ar atmosphere with 5% of H2, whereas the in-situ reduction consisted of focusing the microscope electron beam at 300 kV over a reduced area of the sample. On the sample treated ex-situ, we have obtained HRTEM micrographs showing the effects of reduction in a hydrogen atmosphere (transformation of SnO2 into SnO in localised patches as well as nucleation of Pd nanoclusters). On the in-situ reduced sample, we could additionally obtain HRTEM micrograph sequences showing the reduction process in real-time. Epitaxial relationships between metal clusters and the semiconductor support also have been studied using supercell models and their corresponding computer simulations.
