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 H2O2 and applied to the catalytic combustion of dichloromethane (DCM). The experimental results show that the optimal (1 H2O2)-Ru@TiO2 catalyst sample yields 90% DCM conversion at 301 °C, which is 40 °C lower than the temperature required by the (0 H2O2)-Ru@TiO2 catalyst. This good activity is related to its high number of acid sites (especially Brønsted acid sites), an appropriate amount of uniformly dispersed RuO2 particles, and strong interaction between RuO2 and the TiO2 support. In addition, excessive H2O2 leads to the growth and phase segregation of RuO2, which weakens the interaction between RuO2 and the TiO2 support and decreases catalytic activity. Moreover, H2O2 addition also contributes to the stability of catalysts, which possibly results from the re-dispersion of RuO2 on the TiO2 support during the reaction.