Different reactive behaviours of dichloromethane over anatase TiO2 supported RuO2 and V2O5

Three catalysts with RuO2 and V2O5 as the active components loaded on anatase TiO2 were prepared and used for the catalytic decomposition of dichloromethane (DCM). The V2O5/TiO2 showed higher CO selectivity and lower CH3Cl selectivity than RuO2/TiO2. Further characterization of these samples demonstrated that the V2O5 loading can promote the acidity of TiO2, which is beneficial for the adsorption of DCM and cleavage of C-Cl bonds, thus leading to a higher low temperature catalytic activity than RuO2/TiO2. Meanwhile, the EDS-mapping and XRD results indicated that RuO2 agglomerated over the surface of anatase TiO2. Therefore, a portion of the DCM directly decomposed over the bare surface of TiO2 and led to the production of CH3Cl, which is more stable than CH2Cl2 and difficult to decompose. However, the loading of RuO2 greatly enhanced the redox properties of the catalyst by enriching the surface oxygen species and promoted the deep oxidation processes to improve the selectivity of the product to CO2. Finally, the RuO2&V2O5/TiO2 catalyst was synthesized and used for the decomposition of DCM. The results demonstrated that the RuO2&V2O5/TiO2, which coupled the oxidation centre (RuO2) with the acid centre (V2O5), shows wonderful prospects for application in DCM decomposition.