1,2-Dichloroethane Deep Oxidation over Bifunctional Ru/Ce_<i>x</i>Al_<i>y</i> Catalysts

Ru/Ce_<i>x</i>Al_<i>y</i> catalysts were synthesized with impregnation of RuCl₃ aqueous solution on Ce_<i>x</i>Al_<i>y</i> (Al₂O₃–CeO₂) and used in 1,2-dichloroethane (1,2-DCE) oxidation. Characterization by X-ray diffraction, Raman, NH₃-temperature-programmed desorption (TPD), CO₂-TPD, X-ray photoelectron spectroscopy, and H₂-temperature-programmed reduction indicates that CeO₂ exists as a form of face-centered cubic fluorite structure, whereas the chemical states and the structure of Ru species are dependent on the Ce content. The reducibility and acidity of catalysts increase with Ce/Ce + Al ratio. However, the latter is promoted only in a Ce/Ce + Al range of 0–0.25 and then decreases quickly. Ru/Ce_<i>x</i>Al_<i>y</i> catalysts have considerable activity for 1,2-DCE combustion. TOF_Ru of 1,2-DCE oxidation increases with strong acid, which is ascribed to a synergy of reducibility and acidity. Ru greatly inhibits the chlorination through the decreases in both Cl deposition and CH₂CHCl formation. High stability of Ru/Ce₁₀Al₉₀ maintains at 280 °C for at least 25 h with CO₂ selectivity of 99% or higher. In situ Fourier transform infrared spectroscopy indicates that 1,2-DCE dissociates to form ClCH₂–CH₂O– species, which is an intermediate species for the production of CH₃CHO and CH₂CHCl, the former responsible for deep oxidation