Thermal stability of Pd supported on single crystalline SiO2 thin films

The effect of annealing temperature on a model Pd/SiO2 catalyst has been investigated using Auger electron spectroscopy (AES) and scanning tunneling microscopy. Pd clusters on a single crystalline SiO2 thin film are not altered with respect to size or shape upon heating to 700 K; however, interdiffusion and sintering of the Pd clusters take place between 750 and 1050 K. At 1000 K, AES data imply the formation of Pd–silicide. Above 1050 K, desorption of Pd occurs concomitant with the decomposition of SiO2.