Morphology-Dependent SnO₂ Supported Ru Catalysts for Catalytic Oxidation of Vinyl Chloride Emission

Constructing catalytic materials with specific morphologies is an effective approach to boosting and optimizing their catalytic performances. Herein, SnO₂ supports with diverse morphologies of nanosphere, nanosheet and nanorod were separately synthesized for the fabrication of supported Ru catalysts. Catalytic evaluation results for vinyl chloride (VC) oxidation reveal that the nanosphere-shaped catalyst (Ru/SnO₂-Sp) exhibits the optimum catalytic activity (achieving 90% of VC conversion at 268 °C), exceptional long-term catalytic durability, and cyclic stability comparable to nanosheet-shaped and nanorod-shaped catalysts (Ru/SnO₂-Sh and Ru/SnO₂-Rd). Additionally, Ru/SnO₂-Sp presents promising applicability with regard to its impressive resistance behavior towards carbon dioxide and water vapor interference. Characterization results clearly demonstrate the close structure–activity relationship, primarily depending on the physicochemical parameters of specific surface area, redox capacity, surface oxygen species and valence state distribution of Ru. In situ infrared spectroscopy clarifies the key catalytic pathways of VC oxidation over Ru/SnO₂-Sp, evidencing that the enol species from C-Cl bond cleavage and initial activation of VC molecules and the carboxylic acid species resulting from the subsequent oxidation of enol are both recognized as the crucial organic intermediates.