Study On The Preparation And Catalytic Properties Of Vanadium Oxide Compounds

Vanadium oxide compounds are widely existed in nature,being of complex structures and variable valence states,which are one of the potential catalysts with excellent performance.The advanced oxidation technology based on activating persulfate has became one of promising methods in the field of wastewater treatment,being of strong oxidation and degradation ability,fast reaction rate,simple operation and clean product,which is widely used in removing various refractory organic pollutants.Therefore,in this work,vanadium oxide catalysts were prepared,and their catalytic performances of activating persulfate for the degradation of organic pollutants in water were explored.The specific research contents are as follows:（1）Three kinds of V₂O₅ catalysts,V₂O₅ nanospheres（V_S）,V₂O₅ nanowires（V_W）,and V2O5 nanorods（VR）,with different morphologies were synthesized by the hydrothermal method,and characterized by X-ray powder diffraction（XRD）,scanning electron microscopy（SEM）and X-ray photoelectron spectroscopy（XPS）.The degradation of azo dye Acid Orange（AO7）by three kinds V2O5 catalysts was studied.The results show that the sequence of catalytic activity for the materials is:V_W>V_S>V_R,which is probably caused by the the larger surface area was more conducive to the catalytic reaction;both SO₄^-·and·OH radicals are found to take part in the catalytic oxidation reaction,in which SO₄^-·is the main active group for degradation of AO7;after three cycles,the three materials can still effectively degrade AO7,suggesting that the three catalysts have good stability.（2）Cu doped V₂O₅（Cu-V₂O₅）catalyst was prepared by the hydrothermal method and characterized by XRD,XPS and TEM.Taking benzotriazole（BTA）as the target pollutant,it was found that the catalytic activity of Cu-V2O5 nanoparticles was better than that of pure V2O5,which was due to the synergistic effect between vanadium ion and copper ion.SO₄^-·,·OH,and O₂^-·radicals were all involved in the catalytic oxidation,and SO₄^-·was the most important type of free radicals in BTA degradation.After three cycles,Cu-V₂O₅ could still degrade BTA effectively,which showed that the catalyst has good stability.（3）Oxygen vacancy V2O5 catalyst was prepared by a simple physicochemical method.It was characterized by XRD,TEM and XPS.With AO7 as the target pollutant,it was found that oxygen vacancy V₂O₅ nanoparticles had better catalytic activity than pure V₂O₅,because of the presence of oxygen vacancy promoting the catalytic reaction.SO₄^-·,·OH,¹O₂ and O₂^-·were all involved in the catalytic oxidation reaction,and SO₄^-·was found to play the most important role in AO7 degradation.After three cycles,oxygen vacancy V2O5 could still degrade AO7 effectively,indicating that the catalyst has good stability.