The Construction Of Titanium Oxide Based Grading Structure And Low Temperature SCR Denox Performance

The most widely used flue gas denitration（deNOx）technology is selective catalytic reduction（SCR）.The commercial V₂O₅-WO₃/TiO₂ catalyst has the disadvantages of high operating temperature and narrow active temperature window.Therefore,in recent years,researchers have focused on developing efficient low-temperature SCR catalysts.Among them,manganese-based catalysts exhibit excellent low-temperature activity,but there are still problems with poor SO₂ resistance and reshaping of powders.To solve the above problems,this paper proposed that taking Cordierite ceramics as the carrier,in situ growth of titanium dioxide nanorods（TiO₂ nanorods）by hydrothermal method,and adopting cerium-anganese as active components to prepare hierarchical structure SCR deNOx catalysts.The physical and chemical properties of the catalysts were systematically studied and the catalytic reaction mechanism was also investigated by in situ DRIFTS.Good arrays were filterrd by the morphology of the TiO₂ nanorods and the deNOx performance of MnO_X supported on them.It was determined that the preparation condition of good arrays were 0.2mol/L seed concentration,12.5mL hydrochloric acid,12.5mL deionized water,600μL tetrabutyl titanate and hydrothermal reaction at 180℃for 8 hours.Two series of catalysts were prepared by impregnation and sol-impregnation methods.Studies had showed that the catalysts prepared by sol-impregnation method had more mesoporous structure,Lewis acid sites,Mn³⁺,surface active oxygen O_α,and stronger reduction ability compared with the catalysts prepared by impregnation method.The catalysts prepared by sol impregnation had showed excellent efficiency up to 100%at 200℃.However,the sol-impregnation method had weaker sulfur resistance than the impregnation method.In situ DRIFTS indicated that the catalysts prepared by both methods followed the L-H and E-R reaction pathway.The catalysts prepared by the sol-impregnation method easily followed the L-H pathway with lower chemical energy.Ce doped catalyst were made by impregnation method.Studies have showd that Ce doping not only improved deNOx efficiency but also improved sulfur resistance.Ce doping can provide more Mn³⁺and surface active oxygen O_αwhich lead to improve the efficiency of deNOx.Ce doping made Br?nsted acid sites stronger.In situ DRIFTS indicated that the doping of Ce only affected the NO adsorption species and did not change the reaction pathway.