ToF-SIMS studies of the surface of Pd/ZrO₂-TiO₂ catalyst used in the hydrodechlorination process

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used in order to obtain the information about the surface composition of Pd/ZrO₂-TiO₂ catalyst and to estimate the changes in the concentration of particular components on its surface during the hydrodechlorination of CCl₄. The results demonstrated that the hydrodechlorination process led to the increase in the concentration of chlorine and the drop in the amount of surface accessible palladium, while the quantity of Pd-Cl bounds did not change considerably. It suggested that the presence of ZrO₂ protected the surface of the studied catalyst against the formation of PdCl₂.