Pt-, Pd-, and Ru-doped bimodal mesoporous TiO₂ catalysts were prepared by wet impregnation and applied to the catalytic combustion of dichloromethane (DCM). The Pd/TiO₂ and Ru/TiO₂ catalysts exhibited excellent catalytic activity. Total oxidation of DCM was obtained at 335 °C with less undesired CO and byproducts (C_xH_yCl_z). A certain decrease in the selectivity of the Pd/TiO₂ catalyst was observed in a long-term stability test, whereas Ru/TiO₂ displayed appreciable stability. Pt/TiO₂ was easily deactivated and showed the poorest performance for DCM decomposition. Deactivation of the catalysts was related to the deposition of carbon species and chlorine poisoning, whereby the active sites for DCM decomposition were occluded. Furthermore, the adsorption of chlorine species could change the chemical states of the Pd or Pt species and generate inactive species. Deactivation of the Ru/TiO₂ catalyst was inhibited to some extent as carbon and chlorine species could be removed by RuO₂. Moreover, the larger pore-size distribution of Ru/TiO₂ was favorable for the desorption of by-products during DCM oxidation.

通过湿法浸渍制备了Pt，Pd和Ru掺杂的双峰介孔TiO ₂催化剂，并将其应用于二氯甲烷（DCM）的催化燃烧。Pd / TiO ₂和Ru / TiO ₂催化剂表现出优异的催化活性。在335°C下获得了DCM的总氧化，生成了较少的不希望的CO和副产物（C _x H _y Cl _z）。在长期稳定性测试中，观察到Pd / TiO ₂催化剂的选择性有所降低，而Ru / TiO _2则表现出明显的稳定性。铂/钛₂容易失活，显示出最差的DCM分解性能。催化剂的失活与碳物质的沉积和氯中毒有关，从而堵塞了DCM分解的活性位。此外，氯物种的吸附会改变Pd或Pt物种的化学状态，并产生非活性物种。Ru / TiO ₂催化剂的失活在一定程度上受到抑制，因为RuO ₂可以除去碳和氯。而且，Ru / TiO ₂的较大的孔径分布有利于DCM氧化过程中副产物的解吸。