氨气还原氮化五氧化二钒制备V(N, O)粉体与机理研究

Study on the preparation of V(N, O) powder by reduction of V2O5 with ammonia at low temperatures

  • 摘要: 通过氨气还原五氧化二钒(V2O5),在773~873 K下成功地制备V(O, N)粉体.利用X射线衍射(XRD),场发射扫描电子显微镜(FE-SEM),热重力分析(TGA),X射线光电子能谱(XPS),化学分析和比表面积(BET)等材料表征方法,分析了V2O5还原成V(O, N)过程中的物相和形貌演变.根据XRD,XPS和化学分析结果,最终产物应为V(O, N);钒源的物相转变顺序依次为:V2O5→VO2→V4O7→V2O3→V(O, N).另外,还研究了氨还原过程中的形态演变,发现除了VN颗粒看上去似乎是由无数个小的VN晶粒组成外,VN颗粒的尺寸和形状与V2O5几乎保持相同.

     

    Abstract: Vanadium nitride is successfully prepared via the reduction of V2O5 in ammonia atmosphere in the temperature range of 773 K to 873 K. Phase transitions and morphology evolutions during the reduction of V2O5 to VN were analyzed by X-ray diffraction (XRD) and Field-emission scanning electron microscope (FE-SEM), respectively. Thermal Gravity Analysis (TGA), X-ray photoelectron spectroscopy (XPS), chemical analysis and Brunauer Emmett Teller (BET) were used to material characterizations. According to the results of XRD, XPS and chemical analysis, the final products should be V(N, O) and the reaction sequence of V2O5 with ammonia from 773 K to 873 K was: V2O5→VO2→V4O7→V2O3→V(O, N). Regarding the morphology evolutions during the ammonia reduction process, the size and shape of VN particle were almost kept the same as that of V2O5, except that one VN particle were composed of many small VN grains.

     

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