Crystal Engineering of TiO₂ for Enhanced Catalytic Oxidation of 1,2-Dichloroethane on a Pt/TiO₂ Catalyst

Crystal engineering of metal oxide supports represents an emerging strategy to improve the catalytic performance of noble metal catalysts in catalytic oxidation of chlorinated volatile organic compounds (CVOCs). Herein, Pt catalysts on a TiO₂ support with different crystal phases (rutile, anatase, and mixed phase (P25)) were prepared for catalytic oxidation of 1,2-dichloroethane (DCE). The Pt catalyst on P25-TiO₂ (Pt/TiO₂-P) showed optimal activity, selectivity, and stability, even under high-space velocity and humidity conditions. Due to the strong interaction between Pt and P25-TiO₂ originating from the more lattice defects of TiO₂, the Pt/TiO₂-P catalyst possessed stable Pt⁰ and Pt²⁺ species during DCE oxidation and superior redox property, resulting in high activity and stability. Furthermore, the Pt/TiO₂-P catalyst possessed abundant hydroxyl groups, which prompted the removal of chlorine species in the form of HCl and significantly decreased the selectivity of vinyl chloride (VC) as the main byproduct. On the other hand, the Pt/TiO₂-P catalyst exhibited a different reaction path, in which the hydroxyl groups on its surface activated DCE to form VC and enolic species, besides the lattice oxygen of TiO₂ for the Pt catalysts on rutile and anatase TiO₂. This work provides guidance for the rational design of catalysts for CVOCs.