Preparation And Characterization Of Ni-V Catalysts For Dichloromethane Combustion

Chlorinated volatile organic compounds(CVOCs) was widely applied in all kinds of chemical production process, was one of the main pollutions caused atmospheric environment. The catalytic combustion is an effective and energy saving technology of the current abatement for CVOCs. This article selected transition metal Ni and V as the active component, prepared the double metal oxide catalyst. Dichloromethane(DCM) was chosen as model compound of Chlorine Volatile Organic Compounds(CVOCs). The catalysts were examined in the oxidation of DCM and in the selectivity toward HCl. The texture and physical-chemical characteristic of the catalysts for DCM were investigated by BET(specific surface area), XRD(X-ray diffraction) and SEM(scanning electron microscope).The Al2O3, ZrO2 and TiO2 with different crystal structure were selected as supports for preparing double metal oxide catalyst with Ni and V as the active component. The results showed that the catalysts prepared by Al2O3 and TiO2(anatase phase, calcinating at 500℃) with 10%wt Ni-V loading(Ni, V mole ratio is 1, the same below) had the best catalytic activity and selectivity toward HCl. Al2O3 had the highest specific surface area with TiO2(500℃) following. And their surface morphology did not change much after loading active component. When the calcination temperature rised, the catalysts, just like 10%Ni-V/ZrO2, sintered, grain size increased, the NiV2O6 crystal phase appeared and specific surface area fallen, these changes greatly reduced the catalysis activity.To select the Ti O2 as the carrier, investigated effects of active component of Ni-V/TiO2 catalyst for DCM. Results show that the conversion of DCM was inversely proportional to the coating amount of active component. As the active component loading increased, the specific surface area decreased and the catalysis activity decreased. When the load of active components were 1% or 2%, catalysts had the best activity, selectivity toward HCl and stability for DCM degradation. As the active component loading increased, the catalyst channel blocked, the number of active site per unit area reduced, the dechlorination of catalysts reduced, the catalysts deactivation occurred finally.Based on the research of Ni-V/Ti O2 powder catalysts, the Ni-V/TiO2/cordierite monolithic catalysts were prepared by in situ coating technology. Different loading amount of TiO2 and Ni-V were investigated for DCM oxidation. 2%-NiV/10%-Ti O2/cordierite monolithic showed the best catalytic performance and good selectivity to CO2 and HCl.