本文選題：稀土摻雜　切入點(diǎn)：ZnO　出處：《內(nèi)蒙古農(nóng)業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：木材加工工業(yè)廢水中含有大量難降解、有毒的有機(jī)污染物,已經(jīng)嚴(yán)重威脅著人類的生存發(fā)展,治理工業(yè)廢水污染問題勢在必行。光催化技術(shù)在常溫、常壓條件下可以有效的降解廢水中的有機(jī)污染物,且不會(huì)造成二次污染。半導(dǎo)體光催化材料氧化鋅(ZnO)相比其他催化劑,具有著較好的物理和化學(xué)穩(wěn)定性,且無毒無害,價(jià)格低廉。過渡金屬、堿土金屬、稀土金屬等摻雜能夠改變ZnO的禁帶寬度、晶體形貌結(jié)構(gòu)等,是有效提高光催化性能的重要途徑。很多稀土氧化物如氧化鑭,氧化釹等可以有效提高和改善催化劑的穩(wěn)定性和活性。本論文主要從稀土元素鉺(Er)、釓(Gd)、鋱(Te)著手,分別通過共沉淀法和溶膠-凝膠法制備了一系列稀土摻雜的ZnO光催化劑,分別探究了不同制備方法下不同焙燒溫度、不同稀土元素?fù)诫s和不同摻雜量對ZnO光催化劑的結(jié)構(gòu)、形貌和活性影響。并通過掃描電鏡(SEM)、X-射線粉末衍射(XRD)、比表面積(BET)、紫外可見漫反射(UV-Vis DRS)等技術(shù)對制備的光催化劑進(jìn)行分析表征。主要內(nèi)容簡述如下:(1)利用共沉淀法制備稀土摻雜ZnO光催化劑,以紫外光下催化降解亞甲基藍(lán)(MB)和甲基橙(MO)作為反應(yīng)探針,研究了不同稀土(Er、Gd、Te)摻雜ZnO光催化劑,對稀土摻雜ZnO光催化劑的結(jié)構(gòu)、形貌和光催化活性進(jìn)行分析表征。研究結(jié)果表明:隨著焙燒溫度和稀土摻雜量增加,催化劑的結(jié)晶性和純度都比較好,稀土摻雜有效引起ZnO平均晶粒尺寸的改變,比表面積和孔徑大小發(fā)生改變,比表而積大的樣品其光催化活性均比較強(qiáng),UV-Vis DRS說明不同稀土元素?fù)诫s對ZnO的帶隙影響較小,與未摻雜ZnO對比,吸收帶邊無變化或略微藍(lán)移。SEM圖像分析可知不同摻雜量的光催化劑其形貌有著顯著的變化。通過篩選優(yōu)化影響光催化體系的因素,在500℃焙燒溫度下,相比于未摻雜ZnO的降解率MB(MO)92.6%(42.4%),0.5at%Er/ZnO、0.5at%Gd/ZnO和3at%Te/ZnO展現(xiàn)出較好的光催化活性,在紫外光照射 2h 后,MB(MO)的降解率分別達(dá)到了 94.5%(60%)、95.9%(56%)、98.4%(57.7%)。(2)利用溶膠-凝膠法制備稀土摻雜ZnO光催化劑,以紫外光下催化降解MB和MO作為反應(yīng)探針,研究了不同稀土(Er、Gd、Te)摻雜ZnO光催化劑,對ZnO的結(jié)構(gòu)、形貌和光催化活性進(jìn)行分析表征。研究結(jié)果表明:隨著焙燒溫度和稀土摻雜量增加,XRD各圖譜中的衍射峰強(qiáng)度變化并不明顯,均沒有雜相產(chǎn)生,樣品結(jié)晶度良好。BET數(shù)據(jù)表明,催化劑的比表面積均呈現(xiàn)不同變化趨勢。SEM分析可知,相比于未摻雜,稀土摻雜氧化鋅對光催化劑的形貌有明顯的影響,UV-vis DRS說明不同稀土元素?fù)诫s對ZnO的帶隙影響較小。由光催化活性測試可知,對比于未摻雜ZnO,稀土摻雜ZnO對有機(jī)污染物亞甲基藍(lán)和甲基橙的降解效果均有不同程度的改善提高。在三種稀土(Er、Gd、Te)摻雜ZnO催化劑中,50℃焙燒溫度下,相比于未摻雜ZnO的降解率MB(MO)42.7%(22.1%),lat%Er/ZnO、0.5at%Gd/ZnO和1at%Te/ZnO分別具有較高的光催化活性,光催化對MB(MO)的降解率分別為 90.7%(40.3%)、91.7%(49.1%)、68.9%(29.5%)。
[Abstract]:Wood processing industry wastewater contains large amounts of refractory, toxic organic pollutants, has been a serious threat to human survival and development, it is imperative to waste water treatment of industrial pollution. The photocatalytic technology at room temperature, can effectively degrade organic pollutants in the atmospheric conditions, and will not cause two pollution. (Zinc Oxide semiconductor photocatalytic materials ZnO) compared with other catalysts, has good physical and chemical stability, non-toxic and harmless, low price. Transition metal, alkaline earth metal, rare earth metal doping can change ZnO bandgap, crystal morphology and structure, is an important way to improve the photocatalytic performance. Many rare earth oxides such as lanthanum oxide, neodymium oxide can effectively improve the stability and activity of the catalyst. This paper mainly from the rare earth Er (Er), gadolinium (Gd), terbium (Te) with hand, respectively by co precipitation method and solution A series of rare earth doped ZnO photocatalyst prepared by sol gel method, we studied the different preparation methods under different calcination temperature, the structure of different rare earth element doping and doping amount of ZnO photocatalyst. The effect of morphology and activity. By scanning electron microscopy (SEM), X- ray diffraction (XRD). The specific surface area (BET), UV Vis diffuse reflectance (UV-Vis DRS) to analyze the properties of the photocatalyst was technology. The main contents are described as follows: (1) the preparation of rare earth doped ZnO photocatalyst by coprecipitation method, the photocatalytic degradation of methylene blue (MB) and methyl orange (MO) as the reaction probe of different rare earth (Er, Gd, Te) doped ZnO photocatalyst, the structure of rare earth doped ZnO photocatalyst, the characterization of morphology and photocatalytic activity. The results show that with the calcination temperature and doping amount of rare earth catalyst, crystalline and pure Are relatively good, rare earth doped effectively by ZnO the average grain size, specific surface area and pore size change, surface area of large samples of their photocatalytic activity was relatively strong, UV-Vis DRS shows little effect on the band gap of ZnO doped with different rare earth elements, the UN doped ZnO contrast, absorption band while no change or slightly blue shift of the image analysis of.SEM photocatalyst shows different doping amount the morphology changes significantly. Through factor screening optimization effects on photocatalytic system, calcination temperature at 500 DEG C, compared to the undoped ZnO degradation rate of MB (MO) 92.6% (42.4%), 0.5at%Er/ZnO, 0.5at%Gd/ZnO and 3at%Te/ZnO show good photocatalytic activity under UV irradiation, 2h, MB (MO) degradation rate reached 94.5% (60%), 95.9% (56%), 98.4% (57.7%). (2) prepared by the sol-gel method of rare earth doped ZnO photocatalyst with UV light catalytic The degradation of MB and MO as probe reaction, effects of different rare earth (Er, Gd, Te) doped ZnO photocatalyst, the structure of ZnO, the characterization of morphology and photocatalytic activity. The results show that with the calcination temperature and doping amount increase, the diffraction peak of XRD of the intensity of the change is not obvious, no impurity phase, the sample was well crystallized.BET data show that the specific surface area of the catalyst showed a different trend in.SEM analysis, compared to the undoped, have obvious effect on the morphology of photocatalyst doped with rare earth UV-vis DRS Zinc Oxide, that gap has little effect on ZnO of different rare earth doped by photocatalysis. Activity test showed that compared to the undoped ZnO, were improved the degradation of organic pollutants in rare earth doped ZnO methylene blue and methyl orange. In three kinds of rare earth (Er, Gd, Te) doped ZnO catalyst, 50 C Under the calcination temperature, the degradation rate of MB was (MO) 42.7% (22.1%) compared with the undoped ZnO, and lat%Er/ZnO, 0.5at%Gd/ZnO and 1at%Te/ZnO had higher photocatalytic activity respectively. The degradation rate of photocatalytic MB (MO) was 90.7% (40.3%), 91.7% (49.1%), 68.9% (29.5%), respectively.

【學(xué)位授予單位】：內(nèi)蒙古農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：X798;O643.36

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