本文關(guān)鍵詞：稀土改性鉍基光催化劑制備及其對(duì)高濃度染料的光催化降解性能研究　出處：《江西理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 稀土 鉍基 Bi2O3 Bi2MoO6 BiOCl 光催化 高濃度染料

【摘要】：半導(dǎo)體光催化氧化技術(shù)能利用光能完全礦化有機(jī)污染物,在水處理領(lǐng)域中具有廣泛的應(yīng)用前景。鉍基半導(dǎo)體化合物具有價(jià)廉、環(huán)保的特點(diǎn),已經(jīng)成為新型光催化劑開發(fā)領(lǐng)域的研究熱點(diǎn)。稀土因其獨(dú)特的電子結(jié)構(gòu)是一種重要的改性劑。稀土改性鉍基光催化劑目前鮮有報(bào)道,尤其缺少系統(tǒng)性研究稀土對(duì)鉍基光催化劑改性。目前也缺少針對(duì)光催化降解高濃度污染物的研究。本文以降解高濃度污染物為目標(biāo),首先系統(tǒng)研究了摻雜鑭系元素對(duì)Bi2O3光催化性能的影響。在此基礎(chǔ)上,通過稀土離子摻雜與稀土氧化物復(fù)合進(jìn)一步研究稀土對(duì)鉍基光催化劑結(jié)構(gòu)與性能的影響。主要研究?jī)?nèi)容如下:1.采用水熱-熱處理法制備稀土摻雜Bi2O3光催化劑�？疾炝瞬煌⊥猎丶盁崽幚頊囟葘�(duì)光催化性能的影響。結(jié)果表明:摻入稀土有效抑制Bi2O3由β-Bi2O3向α-Bi2O3的相轉(zhuǎn)變,有助于β-Bi2O3相穩(wěn)定。稀土摻雜使樣品不同程度的紅移并將光吸收范圍拓展到550 nm以上。可見光照射下高濃度酸性橙II的光催化降解實(shí)驗(yàn)表明,稀土元素?fù)诫sBi2O3具有良好的可見光催化性能,其中輕稀土以Nd、Pr及重稀土Gd、Er摻雜的催化劑可見光催化效率較佳。2.采用水熱-焙燒法制備Eu3+摻雜Bi2MoO6光催化劑。結(jié)果表明,所有樣品均為正交晶系的γ-Bi2MoO6,Eu3+摻雜進(jìn)入Bi2MoO6晶格代替部分Bi3+,Bi2MoO6晶格畸變程度增強(qiáng),結(jié)晶度下降晶粒細(xì)化。Eu3+能夠調(diào)節(jié)Bi2MoO6能帶結(jié)構(gòu),降低Bi2MoO6禁帶寬度。由于Eu3+和Eu2+之間可以相互轉(zhuǎn)換,提高了光生電子和空穴的分離,光催化活性得到顯著提高。3.采用了沉淀法制備BiOCl前驅(qū)體,再利用研磨焙燒法合成La2O3復(fù)合光催化劑。該系列催化劑均具有較好的結(jié)晶性能,具有片狀形貌。La可取代BiOCl晶格中部分Bi。討論了不同復(fù)合含量和焙燒溫度對(duì)合成樣品的光催化性能的影響,并且當(dāng)La的復(fù)合量為1 wt%,200℃焙燒3 h,La2O3/BiOCl樣品的光催化效率最佳。La2O3/BiOCl在高濃度染料降解中表現(xiàn)出更好的光催化性能,這主要是由于復(fù)合La2O3后,La3+提供有利于的氧化-還原勢(shì)阱成為光生電子缺陷,阻止了電子-空穴對(duì)的復(fù)合。綜合表明,稀土能夠調(diào)控鉍基化合物的晶體結(jié)構(gòu)、光吸收性能并抑制光生電子-空穴對(duì)的復(fù)合,從而可以大幅度提高鉍基化合物降解高濃度有機(jī)污染物的光催化性能。
[Abstract]:Semiconductor photocatalytic oxidation technology can use light energy to completely mineralize organic pollutants, and has a wide application prospect in the field of water treatment. Bismuth based semiconductor compounds have the characteristics of low price and environmental protection. Rare earth is an important modifier because of its unique electronic structure. Rare earth modified bismuth based photocatalyst is rarely reported at present. In particular, there is a lack of systematic study on the modification of bismuth-based photocatalysts by rare earths. At present, there is no research on photocatalytic degradation of high-concentration pollutants. The aim of this paper is to degrade high-concentration pollutants. The effect of doped lanthanide on the photocatalytic properties of Bi2O3 was studied. The effects of rare earth on the structure and properties of bismuth based photocatalysts were further studied by doping rare earth ions with rare earth oxides. The main contents are as follows:. 1. Rare earth doped Bi2O3 photocatalysts were prepared by hydrothermal heat treatment. The effects of rare earth elements and heat treatment temperature on photocatalytic properties were investigated. The phase transition of Bi2O3 from 尾 -Bi _ 2O _ 3 to 偽 -Bi _ 2O _ 3 was effectively inhibited by the addition of rare earth. It is helpful for the stability of 尾 -Bi _ 2O _ 3 phase. Rare earth doping makes the samples red-shift to varying degrees and expands the absorption range to 550. The photocatalytic degradation of acid orange II with high concentration under visible light irradiation was studied. Rare earth element doped Bi2O3 has good visible light catalytic performance, among which the light rare earth is NdPr and the heavy rare earth Gd. The visible light catalytic efficiency of er doped catalyst was better. 2. Eu3 doped Bi2MoO6 photocatalyst was prepared by hydrothermal calcination method. All the samples were doped with 緯 -Bi2MoO6EU _ 3 into the Bi2MoO6 lattice instead of part of the Bi3 _ 2MoO _ 6 crystal lattice, and the distortion degree of the crystal lattice was enhanced. The decrease of crystallinity. EU3 can adjust the band structure of Bi2MoO6 and decrease the band gap of Bi2MoO6. Because of the interconversion between Eu3 and Eu2. The photocatalytic activity was improved significantly. 3. The BiOCl precursor was prepared by precipitation method. The La2O3 composite photocatalyst was synthesized by grinding roasting method. The series of catalysts have good crystallization performance. The effects of different composition content and calcination temperature on the photocatalytic properties of the synthesized samples were discussed, and the composition of La was 1 wt%. The photocatalytic efficiency of La _ 2O _ 3 / BiOCl sample calcined at 200 鈩，

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