摘要--釩酸鉍纖維的微波水熱合成及性能研究

1、<p>　　釩酸鉍纖維的微波水熱合成及性能研究</p><p><b>　　摘 要</b></p><p>　　釩酸鉍光催化劑除了其晶體結(jié)構(gòu)之外，其表面吸附行為、表面的微觀結(jié)構(gòu)即粉體形貌也是影響光催化效果非常重要的一個方面。常見的BiVO4多為塊狀、棒狀、片狀、球狀等，而本文則以纖維形貌為主要研究對象。由于得到纖維形貌需使微波水熱前驅(qū)液達到強堿性，使得生成的

2、釩酸鉍只有少量的BiVO4，大部分晶相為非化學計量比的釩酸鉍，因此將通過二次微波處理工藝控制、稀土元素摻雜、表面活性劑改性、二次微波前驅(qū)液pH調(diào)節(jié)等方法在保持形貌的基礎(chǔ)上，改變晶相種類，并得到較好的光催化性能。</p><p>　　本實驗以Bi(NO3)3·5H2O和NH4VO3為原料，以NaOH為pH調(diào)節(jié)劑，通過一次微波水熱處理合成了混合相的基礎(chǔ)粉體A。然后以表面活性劑、稀土元素的硝酸鹽作為摻雜改性物

3、質(zhì)，進行二次微波水熱處理，同時控制二次微波水熱的反應(yīng)條件，二次微波前驅(qū)液pH，分別合成了B、C、D等釩酸鹽混合相粉體。對樣品進行了XRD、FE-SEM、EDS及光催化測試等，研究不同樣品的晶相組成、形貌、元素含量及光催化性能。</p><p>　　經(jīng)過分析測試，A粉體得到了所要的纖維形貌，為Bi2O3、Bi7VO13和BiVO4組成的混合相；以A粉體為基礎(chǔ)粉體，加入表面活性劑后二次微波水熱處理得到B粉體，與A粉體

4、的形貌、組成皆一致，只是結(jié)晶度有所提高；以A粉體為基礎(chǔ)粉體，加入PVP及稀土元素硝酸鹽，控制二次微波水熱處理得到C粉體，形貌保持纖維狀，但晶相組成為Bi8V2O17、Bi1.7V8O16、Bi1.62V8O16和BiVO4的混合相(Gd作用下)以及Bi17V3O33、Bi2VO5.5、和BiVO4的混合相(Eu作用下)，化學計量比皆朝著Bi：V：O=1:1:4的方向變化，在紫外光下照射100min降解率最高達85.21%；以A粉體為基礎(chǔ)

5、粉體，加入SDBS、稀土元素，控制二次微波前驅(qū)液pH制得D粉體，保持了纖維形貌，晶相組成為BiVO4、Bi3.5V1.2O8.25和Bi1.62V8O16。模擬太陽光下照射200min降解率最高達到96.01%，紫外光下照射60min降解率最高達到96.59%，相比之下，性能有了很大的提高。</p><p>　　關(guān)鍵詞：釩酸鉍，二次微波水熱，纖維狀，化學計量比，光催化性能</p><p>

6、　　Study on Microwave Hydrothermal Synthesis and Properties of bismuth vanadate fibers</p><p><b>　　ABSTRACT</b></p><p>　　For bismuth vanadate photocatalyst addition to the crystal str

7、ucture, the adsorption behavior of the powder, the microstructure morphology of the surface also affect the photocatalytic effect very important aspect. </p><p>　　Common BiVO4 mostly are massive, rod, sheet,

8、 shauuxepherical, etc., but this article places the fiber morphology as the main object of study. Since the hydrothermal precursor need to reach a strong alkaline solution to obtain the morphology of the fibers, bismuth

9、vanadate produced only has a small amount of BiVO4 and most of them are with a stoichiometric ratio. so the microwave treatment process by a secondary control, rare earth doped, surfactant-modified, pH adjustment of seco

10、ndary microwave </p><p>　　In this experiment, the base powder A with a mixed phases are synthesized by a microwave hydrothermal treatment with Bi(NO3)3? 5H2O, and NH4VO3 as raw materials and NaOH as a pH adj

11、usting agent. Surfactants and nitrate of rare earth are used as doping elements to get powders B, C and D with controlling the second microwave hydrothermal reaction conditions and pH of secondary microwave precursor sol

12、ution. The synthesized samples were characterized by XRD, SEM, EDS and photocatalytic degradation o</p><p>　　Based on analysis and testing, powder A obtained the desired morphology of the fibers, phases are

13、mixed of Bi2O3, Bi7VO13 and the composition BiVO4; using powder A as the base powder, the surfactant was added to a secondary microwave heat treatment, the morphology, composition of powder A powder B were the same, but