Understanding the role of tungsten on Pt/CeO2 for vinyl chloride catalytic combustion

Spherical CeO₂ synthesized by the hydrothermal process was used as support to prepare Pt/WO₃/CeO₂, and the effects of tungsten (W) contents on activity, stability and polychlorinated by-products were investigated to understand the role of W for vinyl chloride (VC) catalytic oxidation. The introduction of 12 wt% W to Pt/CeO₂ (P12WC) exhibits the highest catalytic activity with 90% conversion of VC at 250 °C, meanwhile the stability improves and the polychlorinated by-products in the tail gas significantly decrease due to the removal of dissociated Cl species in the formation of HCl. The beneficial effects of W on Pt/CeO₂ are closely related to the chemical state of Pt, redox and surface acid sites distribution. The doped W not only makes Pt disperse evenly on the support with the high valence, but also weakens the interaction between Pt and CeO₂ by the formation of Pt–O–W and Pt–O–W–O–Ce species, which facilitates oxygen mobility. In addition, the modification of W species also significantly increases the surface acidity amount and changes the distribution of acid sites.