Rationally Engineered CuSO₄/TiO₂ with Cl Desorption and Intermediate Rapid Oxidation Dual-Reaction Channels for Efficacious 1,2-Dichloroethane Deep Destruction

Suppressing toxic polychlorinated byproducts during chlorinated volatile organic compound (CVOC) destruction remains a critical challenge. Strengthening the Cl desorption and promoting rapid deep oxidation of reaction intermediates, thereby cutting off the interaction between Cl and reaction intermediates, is an effective strategy to prevent the formation of polychlorinated byproducts. Herein, a CuSO₄/TiO₂ catalyst with dual-reaction channels was developed for 1,2-dichloroethane (1,2-DCE) oxidation, featuring S═O-H sites for Cl desorption and Cu-O-S sites for intermediate oxidation. It achieved 90% conversion at 251 °C, with reaction rates 8.3 and 11.0 times higher than those of SO₄^2-/TiO₂ and CuO/TiO₂, respectively. The hybridization of Cu 3d-O 2p enhanced electron transfer of O → Cu, accelerating 1,2-DCE oxidation via the C═C-OH → - COO/C═O → CO pathway. Meanwhile, the Cl species generated after C-Cl dissociation combined with S═O-H and desorbed in the form of HCl, avoiding Cl binding to intermediates and thus inhibiting the generation of CH₃Cl, CH₂Cl₂, CHCl₃, CCl₄, CH₂ClCHCl₂, and CCl₂CCl₂. Notably, the S═O-H species as a dynamic H transfer site could capture the H of the activated intermediates after being consumed by the Cl species during the reaction, restoring the S═O-H structure and achieving stable desorption of Cl species. This study highlights the previously overlooked matching of chlorine desorption with the intermediate oxidation process, offering a highly efficient solution for CVOC purification.