Cocount Shell Active Carbon Supported Composite Oxides As Denitration Catalyst At Low Temperature

Nitrogen oxides is serious harm to the environment and has become the focus of the atmospheric pollution control. Because of the excellent denitration performance, low temperature SCR denitration technology drows a lot of attention. Catalyst is the key factor of SCR denitration, but for now, V/Ti system catalyst, the most widely used catalyst in business system, has many shortages, such as the high working temperature and narrow adjustment window. So catalysts suitable for denitration at low temperature become more and more imperative.In this paper, the cocount shell active carbon (AC) was chosen as the catalyst support, and after pretreated with nitric acid, Mn and other modified elements composite oxides would be carried on by impregnation for denitration at low temperature. The study showed that, pretreating with nitric acid greatly increased the contents of the oxygen-containing groups on the AC surface, which would benefit the adsorption of NH5 and NO. Under the same denitration conditions, the oxided AC supported oxides exhibited higher denitration activities compared to those of the raw AC supported ones. The introduction of TiO2 in manganese oxide enhanced the resistance to SO2, but decreased the denitration activity at low temperature. Comparatively, addition of SiO2 in the oxides improved not only the resistance to SO2 but also the denitration activity. TEM images indicated that SiO2 might effectively reduce the crystal size of the composite oxides and improve the dispersion on the carrier surface. NH3-TPD results showed that the surface acidity of catalysts was improved remarkably after the addition of SiO2. Moreover, XPS results revealed that the relative content of Mn4+in the oxides was increased as well.Finally, DRIFTS was used to detect the surface product of the catalyst MnOx/Oxided-AC. The results showed that NH3 mainly formed hydrogen bond with the oxygen atoms on the surface of the active component on L acid sites, and as for NO, the main form after adsorption was NO2- and NO3-, and finally the possible reaction mechanism was put forward.