The Effect of H2O2 Pretreatment on TiO2-Supported Ruthenium Catalysts for the Gas Phase Catalytic Combustion of Dichloromethane (CH2Cl2)

In the study presented herein, a series of TiO2-supported Ru catalysts were prepared through over-impregnation with different amounts of H2O2and applied to the catalytic combustion of dichloromethane (DCM). The experimental results show that the optimal (1 H2O2)-Ru@TiO2catalyst sample yields 90% DCM conversion at 301 °C, which is 40 °C lower than the temperature required by the (0 H2O2)-Ru@TiO2catalyst. This good activity is related to its high number of acid sites (especially Brønsted acid sites), an appropriate amount of uniformly dispersed RuO2particles, and strong interaction between RuO2and the TiO2support. In addition, excessive H2O2leads to the growth and phase segregation of RuO2, which weakens the interaction between RuO2and the TiO2support and decreases catalytic activity. Moreover, H2O2addition also contributes to the stability of catalysts, which possibly results from the re-dispersion of RuO2on the TiO2support during the reaction.