發(fā)布時(shí)間：2018-05-03 19:55

  本文選題：ZnO + 復(fù)合材料��； 參考：《河南師范大學(xué)》2017年碩士論文

【摘要】：工業(yè)發(fā)展給人類帶來了大量的好處,但是,它也對(duì)我們的生態(tài)系統(tǒng)造成了很多不利的影響。土壤,水和大氣都被嚴(yán)重污染,人類的健康也隨之受到了威脅。因此,消除這些污染迫在眉睫。迄今為止,光催化技術(shù)被認(rèn)為是最現(xiàn)實(shí)的解決方案之一。近年來,ZnO因具有較低的價(jià)格,穩(wěn)定的性能,無毒,高的量子效應(yīng)等優(yōu)點(diǎn),已成為被廣泛應(yīng)用的光催化劑之一。結(jié)構(gòu)決定性能,所以,制備不同形貌和結(jié)構(gòu)的ZnO材料已成為研究者們炙手可熱的課題。但是,在ZnO作為光催化劑的催化過程中,由于光生載流子的分離效率較低,并不能達(dá)到讓人們滿意的光催化效果。因此,為了提高ZnO光生e-和h+的分離效率,大量的研究正在被進(jìn)行。Ag作為一種貴金屬,可以作為光生e-的有效俘獲陷阱,與ZnO復(fù)合能夠快速地轉(zhuǎn)移走ZnO表面的光生e-,從而有效地提高光生h+和e-的分離率,進(jìn)而使ZnO的光催化性質(zhì)得到提高。因此合成獨(dú)特結(jié)構(gòu)和優(yōu)良性能的Ag/ZnO復(fù)合材料具有相當(dāng)重要的科學(xué)意義。本文采用簡(jiǎn)單的溶劑熱合成方法,合成出了多種形貌的ZnO以及ZnO與Ag的復(fù)合材料。主要工作如下:(1)選用乙醇和二乙二醇作為反應(yīng)溶劑,Zn(NO_3)2.6H_2O作為Zn源,采用溶劑熱法一步合成ZnO。通過調(diào)控溶劑比例分別合成了球狀,碗狀和花狀的分級(jí)結(jié)構(gòu)的ZnO。利用EDS,XRD,FESEM,HRTEM,BET,UV vis等測(cè)試手段對(duì)樣品進(jìn)行了表征,并對(duì)樣品的形成機(jī)理進(jìn)行了推測(cè)。實(shí)驗(yàn)選取亞甲基藍(lán)(MB)作為目標(biāo)污染物,在紫外光照射下,對(duì)所制備ZnO的光催化性能進(jìn)行了研究。結(jié)果表明,當(dāng)乙醇和二乙二醇的比為2:1時(shí),合成的球狀ZnO對(duì)MB的降解效率最高。(2)通過兩次簡(jiǎn)單的溶劑熱法合成了中空結(jié)構(gòu)的球狀A(yù)g/ZnO復(fù)合材料。并對(duì)不同Ag修飾量的Ag/ZnO復(fù)合材料進(jìn)行了各類表征。對(duì)Ag/ZnO復(fù)合物光催化性質(zhì)的系統(tǒng)研究表明,Ag的修飾量不同,Ag/ZnO樣品的光催化性質(zhì)有很大不同。在UV光照射下,30%Ag/ZnO復(fù)合物對(duì)羅丹明B(RhB)的降解性能最佳。另外,在本章中,Ag/ZnO復(fù)合材料很好的催化循環(huán)穩(wěn)定性能也得到了證明。(3)采用溶劑熱法一步合成分級(jí)結(jié)構(gòu)的空心球ZnO,在Ag_2CO_3作為Ag源的條件下,再利用一次溶劑熱法合成Ag負(fù)載量不同的Ag/ZnO復(fù)合物,同時(shí),ZnO的形貌和結(jié)構(gòu)保持不變。通過樣品在UV光下降解RhB和MB來評(píng)估所制備Ag/ZnO的光催化活性。Ag的負(fù)載量為20%的Ag/ZnO復(fù)合物對(duì)兩種染料的降解效率最高。光照16分鐘后,20%-Ag/ZnO對(duì)RhB的降解比例可達(dá)到99.3%,對(duì)MB的降解效率可達(dá)98.3%。值得注意的是,20%-Ag/ZnO復(fù)合物對(duì)實(shí)際污染物苯酚也具有很好的降解效果,50 mg/L的苯酚在紫外光照射60分鐘后,幾乎被完全降解。在本章最后,對(duì)可能的光催化機(jī)理以及樣品的穩(wěn)定性也進(jìn)行了細(xì)致而深入地探究。
[Abstract]:Industrial development has brought a lot of benefits to mankind, but it has also had a lot of adverse effects on our ecosystems. Soil, water and atmosphere are seriously polluted and human health is threatened. Therefore, the elimination of these pollution is urgent. So far, photocatalytic technology is considered as one of the most realistic solutions. In recent years, ZnO has become one of the widely used photocatalysts because of its advantages of low price, stable performance, nontoxic and high quantum effect. The structure determines the properties, so the preparation of ZnO materials with different morphologies and structures has become a hot topic for researchers. However, in the process of ZnO as photocatalyst, because of the low separation efficiency of photogenerated carriers, it can not achieve satisfactory photocatalytic effect. Therefore, in order to improve the separation efficiency of ZnO photogenerated e- and h, a large number of studies are being carried out. Ag, as a precious metal, can be used as an effective trapping trap for photogenerated e-. The photocatalytic properties of ZnO can be improved by combining with ZnO to transfer the photogenerated e-on the surface of ZnO, thus effectively increasing the separation rate of photogenerated h and e-. Therefore, it is of great scientific significance to synthesize Ag/ZnO composites with unique structure and excellent properties. In this paper, various morphologies of ZnO and ZnO / Ag composites were synthesized by a simple solvothermal synthesis method. The main work is as follows: (1) ethanol and diethylene glycol are selected as the reaction solvent ZnNo3 and 2.6H _ 2O as Zn source, and ZnO _ 2O is synthesized by solvothermal method. Spherical, bowl and flower-like ZnO were synthesized by adjusting the solvent ratio. The samples were characterized by vis and the formation mechanism of the samples was speculated. The photocatalytic properties of ZnO prepared by UV irradiation were studied by using methylene blue blue (MBB) as the target pollutant. The results show that when the ratio of ethanol to diethylene glycol is 2:1, the spherical ZnO has the highest degradation efficiency of MB. 2) the hollow spherical Ag/ZnO composite was synthesized by two simple solvothermal method. All kinds of Ag modified Ag/ZnO composites were characterized. The systematic study on the photocatalytic properties of Ag/ZnO complexes shows that the photocatalytic properties of Ag / Ag modified samples are very different. The degradation of Rhodamine B _ (2) RhB by 30 Ag- / ZnO complex under UV irradiation is the best. In addition, in this chapter, the good catalytic cycling stability of Ag- / ZnO composite is also proved. The solvothermal method is used to synthesize the graded hollow sphere ZnO. Under the condition of Ag_2CO_3 as Ag source, The Ag/ZnO composites with different Ag loading amount were synthesized by single solvothermal method, while the morphology and structure of Ag/ZnO remained unchanged. The photocatalytic activity of Ag/ZnO was evaluated by the degradation of RhB and MB in UV light. The degradation efficiency of the two dyes was the highest when the loading of Ag/ZnO complex was 20%. After 16 minutes of illumination, the degradation rate of RhB and MB were 99.3and 98.3, respectively. It is worth noting that the complex of 20% -Agr / ZnO also has a good degradation effect on the actual pollutant phenol. The phenol of 50 mg/L is almost completely degraded after 60 minutes of ultraviolet irradiation. At the end of this chapter, the possible photocatalytic mechanism and the stability of the samples are also studied in detail.
【學(xué)位授予單位】：河南師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O643.36;O644.1

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