Ammonium heptamolybdate was dissolved in water or oxalic acid solution,and then compounded with TiO₂ to prepare MoO _x ?TiO₂ support,and the VO _x /MoO _x ?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 °C,which was better than that of VMoTiH?F prepared by water dissolution.Because there was more MoO _x on the surface of VMoTiO?F,the interaction with VO _x was enhanced,which promoted the production of more low?valence VO _x and surface chemisorbed oxygen (O_α) active species on the surface of the catalyst.At the same time,the interaction between VO _x and MoO _x 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 MoO _x 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.