The Regulation of MoOx State and Its Effect on the Denitration Performance and Thermal Stability of VOx/MoOx-TiO2 Catalysts
Ammonium heptamolybdate was dissolved in water or oxalic acid solution,and then compounded with TiO2 to prepare MoOx-TiO2 support,and the VOx/MoOx-TiO2 catalysts were obtained after loading vanadium by impregnation method.The structure and properties of the catalysts were characterized by XRD,SEM,BET,XPS,H2-TPR and NH3-TPD,and its denitration activity and high temperature aging performance were investigated.The results showed that the denitrification efficiency of VMoTiO-F prepared by oxalic acid-assisted dissolution of(NH4)6Mo7O24 was greater than 80.0%at 210～510 ℃,which was better than that of VMoTiH-F prepared by water dissolution.Because there was more MoOx on the surface of VMoTiO-F,the interaction with VOx was enhanced,which promoted the production of more low-valence VOx and surface chemisorbed oxygen(Oα)active species on the surface of the catalyst.At the same time,the interaction between VOx and MoOx could also improve the low-temperature redox performance and facilitate the electron transfer in the catalytic process.After high temperature aging,VMoTiH-F had more MoOx into the TiO2 lattice than VMoTiO-F,which was helpful to improve the thermal stability of TiO2.However,anatase TiO2 in VMoTiO-A was seriously sintered or even partially transformed into inert rutile crystal during high temperature aging,resulting in the loss of surface acid sites and the reduction of redox properties.Therefore,the denitrification performance of VMoTiH-A catalyst was significantly higher than that of VMoTiO-A.
国家科技期刊平台
NSTL
万方数据
