Sulfur-Engineered Ru/SnO2 Catalysts for Highly Efficient Catalytic Combustion of 1,2-Dichloroethane.

The catalytic combustion of chlorinated volatile organic compounds (CVOCs) requires catalysts with multiple active sites and excellent synergistic effects due to the complex reaction mechanisms involving both C-H and C-Cl bond cleavage as well as deep oxidation processes. Herein, Ru supported on sulfated tin oxide (STO) was designed to demonstrate excellent activity, stability, and water resistance in the catalytic combustion of 1,2-dichloroethane (EDC). The presence of various sulfate species (-OSO3, -H2SO4, -HSO4), which can undergo reversible transformations, enhanced both the acidity and the mobility of H species, thereby facilitating the cleavage of C-H and C-Cl bonds to form the intermediates of vinyl chloride. Moreover, the dispersion of Ru species was significantly enhanced on the STO support, which effectively promoted the deep oxidation of the intermediates. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis demonstrated distinct mechanistic pathways for the two catalysts. On the Ru/SnO2 catalyst, the interaction between surface oxygen species and H species generated through C-H bond dissociation led to hydroxyl group formation, which consequently suppressed deep oxidation. In contrast, on the Ru/STO catalyst, the coordination of -OSO3 groups with these H species to form -HSO4 effectively protected the surface oxygen species, thereby maintaining the oxidative capacity and ultimately facilitating complete EDC combustion.