Evaporation of Pd onto WO3(001) at room temperature leads to the formation of metal nanoparticles which can be imaged directly by scanning tunnelling microscopy (STM). Annealing a surface supporting 20 Å particles to 600 °C leads to agglomeration of the deposited metal. These observations demonstrate that STM provides a real space approach to the investigation of sintering in oxide supported metal catalysts.
