Construction of uniform nanodots CeO₂ stabilized by porous silica matrix for 1,2-dichloroethane catalytic combustion

The construction of uniform nanodots CeO₂ stabilized by porous silica matrix (CeO₂@SiO₂-T) was synthesized by a spontaneous deposition method. Based on the XRD and TEM results, the CeO₂ nanodots were highly dispersed on the porous silica matrix. The characterizations including O₂-TPD, XPS, and NH₃-TPD clarified that CeO₂@SiO₂-T catalysts possessed strong acidity, rich surface adsorbed oxygen species and oxygen mobility, which was beneficial to the improvement of adsorption and catalytic oxidation of 1,2-dichloroethane (DCE). The CeO₂@SiO₂-T catalysts exhibited high performance for DCE oxidation, in which the CeO₂@SiO₂-400 catalyst showed the best performance (T₉₀ = 275 °C at a space velocity of 15000 h⁻¹) and good stability (at 295 °C for 100 h). The characterization and activity test results showed that the richer acid sites were beneficial to the adsorption and activation of DCE, contributing to the subsequent HCl removal and vinyl chloride (VC) formation. Noticeably, the weak acid sites were more favorable for the improvement of catalytic activity. Then major of VC would be oxidized to adsorbed acetate, which could be further decomposed to CO_x and HCl. In addition, trace poly-chlorinated by-products were detected. The abundant surface adsorbed oxygen species and excellent oxygen mobility facilitated the further oxidation rather than the chlorination reactions.