發(fā)布時間：2017-12-31 15:01

  本文關(guān)鍵詞：鉬酸鉍基納米材料的制備及其在光催化中的應(yīng)用　出處：《華東師范大學(xué)》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 光催化 可見光 鉬酸鉍 復(fù)合物 異質(zhì)結(jié)

【摘要】：隨著人口的增加以及工業(yè)化和城市化的加速,各種有機(jī)廢水被大量排放,這嚴(yán)重影響了人類的身體健康以及地球的生態(tài)平衡。因此,治理和控制水體污染成為了環(huán)境領(lǐng)域亟需解決的問題。由于光催化技術(shù)具有氧化能力強(qiáng),無二次污染,能耗低,催化劑可以重復(fù)利用,反應(yīng)條件相對溫和且易于操作等優(yōu)點(diǎn),因此,從環(huán)境保護(hù)與能源利用方面考慮,光催化技術(shù)具有巨大的應(yīng)用前景。目前,科研工作者對光催化的研究主要集中在兩個方面:一個是對常用的TiO2,SnO2與ZnO等寬帶隙半導(dǎo)體進(jìn)行改性,使其光響應(yīng)范圍拓展至可見光區(qū)域;另一種是尋找可響應(yīng)可見光的新型半導(dǎo)體光催化劑,包括一些對可見光響應(yīng)的氧化物,硫化物等。鉬酸鉍作為一種鉍基Aurivillius氧化物半導(dǎo)體,由于其具有獨(dú)特的層狀結(jié)構(gòu)、良好的光學(xué)性能以及優(yōu)異的催化活性,成為了目前光催化領(lǐng)域的一個研究熱點(diǎn)。本論文旨在通過溶劑熱法探索鉬酸鉍的結(jié)構(gòu)對其光催化性能的影響,并通過進(jìn)一步對鉬酸鉍進(jìn)行改性,以獲得更高的光催化性能。本論文主要是圍繞著鉬酸鉍基納米材料的優(yōu)化進(jìn)行研究,通過對其結(jié)構(gòu)與復(fù)合物進(jìn)行優(yōu)化設(shè)計,提高其光催化性能。主要研究內(nèi)容如下:1.通過對溶劑熱溫度的優(yōu)化,發(fā)現(xiàn)合適的溫度可使Bi2Mo06形成蛋黃-殼(yolk-shell)結(jié)構(gòu)。同時,也對yolk-shell結(jié)構(gòu)Bi2MoO6的形成過程展開分析,發(fā)現(xiàn)其無模板形成yolk-shell結(jié)構(gòu)主要是由于Ostwald熟化過程形成。在與納米片結(jié)構(gòu)和納米顆粒結(jié)構(gòu)Bi2MoO6的光催化性能對比發(fā)現(xiàn),yolk-shell結(jié)構(gòu)Bi2MoO6展現(xiàn)出更為優(yōu)異的光催化性能,其對羅丹明B(Rhodamine B,RhB)的光催化降解在240 min內(nèi)可達(dá)97%。這種優(yōu)秀的光催化性能主要?dú)w咎于yolk-shell結(jié)構(gòu)產(chǎn)生的多次光漫反射,從而提高了其對光的捕獲能力。2.對碳納米管(Carbon Nanotube,CNT)與碳球(Carbon Sphere,CS)進(jìn)行酸化使其表面帶有一定的負(fù)電荷。在溶劑熱的過程中,由于碳材料表面負(fù)電荷產(chǎn)生的弱電場作用,Bi2MoO6在CNT或CS周圍迅速成核生長,分別形成交聯(lián)結(jié)構(gòu)Bi2Mo06-CNT復(fù)合物或者核-殼(core-shell)結(jié)構(gòu)CS@Bi2Mo06復(fù)合物。隨著CNT與CS的引入,Bi2MoO6-CNT與CS@Bi2MoO6復(fù)合物的光催化性能與Bi2MoO6相比得到改善,這是由于交聯(lián)結(jié)構(gòu)復(fù)合物以及core-shell結(jié)構(gòu)CS@Bi2MoO6復(fù)合物在光照射下電子可快速轉(zhuǎn)移,從而達(dá)到降低光生-電子空穴對的復(fù)合的目的。優(yōu)化后交聯(lián)結(jié)構(gòu)Bi2MoO6-CNT復(fù)合物在120 min內(nèi)對RhB的降解率在89%。而對于優(yōu)化后的core-shell結(jié)構(gòu)CS@Bi2MoO6復(fù)合物,其在120 min內(nèi)其對RhB的降解率在95%。3.將Bi4-2xMoxO6(x≤1)中Bi與Mo的比例進(jìn)行優(yōu)化,設(shè)計出yolk-shell結(jié)構(gòu)的Bi2.38Mo0.81O6微球。由于Bi2.38Mo0.81O6微球中存在大量的缺陷,因此在光催化過程中產(chǎn)生大量的載流子可以被這些缺陷收集以及轉(zhuǎn)移,從而提高其光催化性能。其中,Bi2.38Mo0.81O6展現(xiàn)出最佳的光催化性能,在120min內(nèi)其對RhB的降解率為99%。再利用GO包裹于Bi2.38Mo0.81O6微球表面,在微波照射下對GO進(jìn)行還原,可得到BMO@RGO復(fù)合物。由于RGO具有良好的電子傳輸性能,且Bi2.38Mo0.81O6與RGO具有良好的接觸以及階梯能級的存在,因此,在光催化過程中其光生載流子可迅速轉(zhuǎn)移,從而達(dá)到降低光生-電子空穴對的復(fù)合的目的,最終實現(xiàn)其光催化性能的提高。優(yōu)化過的Bi2.38Mo0.81O6@RGO復(fù)合物在80 min內(nèi)對RhB的降解率為99%。4.在Bi2MoO6前驅(qū)中加入SnO2與TiO2,可制備出Bi2MoO6-SnO2與Bi2MoO6-TiO2異質(zhì)結(jié)。由于SnO2與TiO2的存在,Bi2MoO6在SnO2或TiO2周圍迅速成核及生長,形成異質(zhì)結(jié)。由于異質(zhì)結(jié)的形成,Bi2MoO6-SnO2與Bi2MoO6-TiO2異質(zhì)結(jié)的光催化性能均得到比較大的改善。這是由于異質(zhì)結(jié)中存在階梯能級結(jié)構(gòu),這種階梯能級結(jié)構(gòu)有利于光生電子的迅速轉(zhuǎn)移,從而有利于光催化性能的改善。其中,優(yōu)化后的Bi2MoO6-SnO2異質(zhì)結(jié)復(fù)合物在150min內(nèi)其對RhB的降解率為97%以及在360 min內(nèi)其對硝基苯的降解率為90%。而對于優(yōu)化后的Bi2MoO6-TiO2異質(zhì)結(jié)復(fù)合物,其在300 min內(nèi)其對苯酚與硝基苯的降解率分別為96%與94%。
[Abstract]:With the increase of population and the acceleration of industrialization and city, all kinds of organic wastewater is discharged, which seriously affected the health of human beings and the earth's ecological balance. Therefore, governance and control of water pollution has become the urgent environmental problem. The photocatalytic technology has strong oxidation ability, no two pollution. Low energy consumption, the catalyst can be reused, relatively mild reaction conditions and easy operation etc., therefore, considering the protection and utilization of energy environment, photocatalytic technology has great application prospect. At present, the research of scientific research workers of photocatalysis mainly concentrated in two aspects: one is the commonly used TiO2, broadband SnO2 and ZnO semiconductor gap was modified to expand the range to the visible light response; the other is to seek new semiconductor photocatalyst in response to visible light, including some of the See the light response of oxides, sulfides. Bismuth molybdate as a bismuth based oxide semiconductor Aurivillius, due to its unique layered structure, good optical properties and excellent catalytic activity, has become a hot research topic in photocatalysis field at present. This paper aims at exploring the structure by solvothermal method of bismuth molybdate on the photocatalytic properties of bismuth molybdate, and through further modification to obtain higher photocatalytic performance. This paper is mainly around the optimization of bismuth molybdate based nano materials was studied, through the optimization design on its structure and composite, improve the photocatalytic performance. The main contents are as follows: 1. through the optimization of the solvent temperature, find the suitable temperature can make the formation of Bi2Mo06 yolk shell (yolk-shell) structure. At the same time, also the formation process of yolk-shell structure Bi2MoO6 expansion analysis, found the No template to form the yolk-shell structure is mainly due to the formation of Ostwald ripening process. In contrast the photocatalytic properties of nano particles and nano structure and Bi2MoO6 structure, yolk-shell structure Bi2MoO6 showed more excellent photocatalytic properties, the Luo Danming B (Rhodamine B RhB) multiple light diffuse reflection of the photocatalytic degradation of up to 240 min 97%. this excellent photocatalytic performance is mainly attributed to the yolk-shell structure, thereby improving the light harvesting ability of.2. on carbon nanotubes (Carbon Nanotube, CNT) and carbon (Carbon Sphere, CS) ball in acidified with a negative charge on the surface. In certain solvothermal process. Due to the weak electric field produced by carbon material surface negative charge, Bi2MoO6 around CNT or CS rapid nucleation and growth, the formation of crosslinked Bi2Mo06-CNT complexes or core-shell structure were (core-shell) CS@Bi2Mo06 complex With the introduction of CNT and CS. The photocatalytic properties of Bi2MoO6 and Bi2MoO6-CNT and CS@Bi2MoO6 composite was improved compared to, this is due to the crosslinking structure of composite structure of CS@Bi2MoO6 and core-shell complexes in the light irradiation electron can quickly transfer, thereby reducing the photogenerated electron hole pairs of composite - purpose. The optimized crosslinking structure of Bi2MoO6-CNT complexes in 120 min the degradation rate of RhB in 89%. and core-shell for the CS@Bi2MoO6 complex structure after optimization, which in 120 min the degradation rate of RhB in 95%.3. Bi4-2xMoxO6 (x = 1) in Bi and Mo than the optimized design of Bi2.38Mo0.81O6 microspheres, yolk-shell structure due to the presence of. A large number of defects of Bi2.38Mo0.81O6 microspheres, resulting in a large number of carriers can be collected and transfer these defects in the photocatalytic process, so as to improve its photocatalytic performance. Among them, Bi2.38Mo0. 81O6 showed the best photocatalytic performance in the 120min, the RhB degradation rate for 99%. using GO coated on the surface of Bi2.38Mo0.81O6 microspheres under microwave irradiation, in the reduction of GO by BMO@RGO, can be complex. Because RGO has good electrontransport properties, and Bi2.38Mo0.81O6 and RGO have good contact and ladder level the existence, therefore, in the photocatalytic process of the photogenerated carriers can quickly transfer, thereby reducing the photogenerated electron hole pairs of composite - to realize its photocatalytic performance. Bi2.38Mo0.81O6@RGO complexes optimized within 80 min the degradation rate of RhB was 99%.4. SnO2 and TiO2 Bi2MoO6 in addition the precursor, Bi2MoO6-SnO2 can be fabricated with Bi2MoO6-TiO2 heterojunction. Due to SnO2 and TiO2, Bi2MoO6 rapid nucleation and growth of around SnO2 or TiO2, forming a heterojunction. Due to the formation of Bi2Mo heterojunction. O6-SnO2 and Bi2MoO6-TiO2 heterojunction photocatalytic performance have been greatly improved. This is due to the existence of ladder level structure of heterojunction, the ladder level structure is conducive to the rapid transfer of photogenerated electrons, which is conducive to improve the photocatalytic performance. Among them, the Bi2MoO6-SnO2 heterojunction complexes in 150min to RhB the degradation rate was 97% and in 360 min the degradation rate of nitrobenzene was 90%. for optimized Bi2MoO6-TiO2 heterojunction complexes after optimization, the within 300 min of phenol and nitrobenzene degradation rate were 96% and 94%.

【學(xué)位授予單位】：華東師范大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TB383.1;O643.36

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中國博士學(xué)位論文全文數(shù)據(jù)庫 前3條

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本文編號：1360247