DFT study on the regeneration of Pt/γ-Al2O3 catalyst: The effect of chlorine on the redispersion of metal species

The redispersion of metal particle on the catalyst support is closely related to the stable operation as well as the regeneration process of catalysts. Pt/gamma-Al2O3 is an important catalytic system for several industrial processes. Sintering of metal particles is usually a big challenge for Pt/gamma-Al2O3, and the redispersion strategies have been developed to reverse the sintering process. In this work, the redispersion of Pt on gamma-Al2O3 surface was studied via molecular simulation based on the density functional theory (DFT). The redispersion process was divided into two steps, the evaporation of Pt atom from the Pt cluster and the capture of Pt species over the Al2O3 surface. The result shows that the addition of HCl during the redispersion is helpful to both of the processes. The oxychlorination can reduce the minimum temperature of the Pt evaporation and increase the maximum allowable temperature of the capture of Pt species, leading to a thermodynamically favored redispersion process. The result explained the mechanism of the redispersion behavior of Pt on the gamma-Al2O3 support during oxychlorination for the Pt/gamma-Al2O3 catalyst. The method can also be extended to the study on the redispersion of other catalytic systems.

Automated summary

In this study, the redispersion of Pt on the gamma-Al2O3 surface was investigated using molecular simulation based on density functional theory (DFT). The addition of HCl was found to be helpful in both the evaporation and capture processes, leading to a thermodynamically favored redispersion.