本文選題：鉬酸鉍　切入點(diǎn)：水熱/溶劑熱法　出處：《西安科技大學(xué)》2017年碩士論文

【摘要】：半導(dǎo)體光催化技術(shù)和光催化材料是解決當(dāng)前能源匱乏和環(huán)境污染的有效手段和研究熱點(diǎn)。在眾多光催化材料中,鉬酸鉍具有簡單的奧里維里斯(Aurivillius)層狀結(jié)構(gòu),良好的可見光響應(yīng)能力,在環(huán)境污染物處理、太陽能光解產(chǎn)氫、氣敏傳感等方面都表現(xiàn)出優(yōu)異的性能。但是,鉬酸鉍光催化劑距離實(shí)際應(yīng)用仍有不少技術(shù)瓶頸,如優(yōu)化合成工藝、設(shè)計(jì)和制備新的催化劑結(jié)構(gòu)、進(jìn)一步提高可見光催化性能。本文將著眼于光催化性能優(yōu)化,研究了表面活性劑對水熱法、溶劑熱法合成鉬酸鉍形貌和催化性能的影響,并通過納米銀負(fù)載和半導(dǎo)體Bi2S3復(fù)合兩種方式進(jìn)一步提高鉬酸鉍的可見光催化性能,主要的研究內(nèi)容和結(jié)論如下:為分析表面活性劑對鉬酸鉍合成、結(jié)構(gòu)與性能的影響,采用不同表面活性劑,通過水熱法優(yōu)化制備了 Bi_2MoO_6納米片。研究了表面活性劑種類(CTAB、KBr、PVP、PEG)對Bi_2MoO_6片狀結(jié)構(gòu)的影響,并探討了其生長機(jī)理,其中采用CTAB可以獲得均勻的鉬酸鉍納米片。當(dāng)CTAB=0.15g時(shí),合成的納米片厚度僅為5～15nm,比表面積為20.551 m2/g。與鉬酸鉍納米粉體相比,CTAB輔助制備的鉬酸鉍納米薄片具有更強(qiáng)的光吸收,低的禁帶寬度和更優(yōu)的光催化活性,3 h光照后,亞甲基藍(lán)(MB)降解率達(dá)到81%。以CTAB為表面活性劑,采用乙二醇/水混合溶劑熱法進(jìn)一步合成了花簇狀Bi_2MoO_6微米球。Bi_2MoO_6微米花簇球是由厚度為10～20 mm的納米片自組裝而成的。通過改變混合溶劑比可以實(shí)現(xiàn)Bi_2MoO_6微米球的形貌和尺寸調(diào)控,分析了花簇狀微米球生長機(jī)理。EG:H2O=8:2時(shí),合成的Bi_2MoO_6花簇狀中空結(jié)構(gòu)比薄片和花簇狀微米球具有更優(yōu)的光催化活性,3 h光照后,MB降解率達(dá)到98%�；谏鲜龌旌先軇岱�,分別通過一步溶劑熱法和光致還原法合成了 Ag負(fù)載的Ag/Bi_2MoO_6復(fù)合納米材料。結(jié)果表明,采用一步溶劑熱法制備的中空球狀A(yù)g/Bi_2MoO_6(Ag=6wt%)較光致還原法制備的樣品具有更窄的禁帶寬度,因而擁有更優(yōu)的可見光吸收效果,在此基礎(chǔ)上進(jìn)一步探討了中空球生長機(jī)理。以一步溶劑熱法制備的Ag/Bi_2MoO_6樣品為光催化劑,經(jīng)3 h光照后,MB降解率達(dá)到90.2%�；诨旌先軇岱�,通過一步溶劑熱法制備了納米棒-微米球Bi2S3/Bi_2MoO_6復(fù)合結(jié)構(gòu)。這種結(jié)構(gòu)中,光生電子可以在Bi2S3和Bi_2MoO_6形成的界面上傳輸,使光生電子-空穴對能夠得到有效分離,提高載流子的遷移速率。制備的Bi2S3/Bi_2MoO_6復(fù)合結(jié)構(gòu)的光催化性能明顯優(yōu)于相同條件下制備的Bi_2MoO_6微米球,經(jīng)3 h光照后,MB的降解率達(dá)到83%。
[Abstract]:Semiconductor photocatalysis and photocatalytic material is an effective means to solve the energy shortage and environmental pollution and research hotspot. In many photocatalytic materials, bismuth molybdate has a simple Olive Chis (Aurivillius) layered structure, visible light response ability, in environmental pollutant treatment, hydrogen production by solar energy, gas sensing etc. have shown excellent performance. However, bismuth molybdate photocatalyst from practical applications there are still many technical bottlenecks, such as optimizing the synthesis process, design and preparation of new catalyst structure, to further improve the photocatalytic performance. This paper will focus on the photocatalytic performance optimization of surfactant by hydrothermal method, influence solvothermal synthesis of bismuth molybdate morphology and catalytic properties, and the nano silver composite semiconductor Bi2S3 load and two ways to further improve the bismuth molybdate visible light catalytic performance, the main The research contents and conclusions are as follows: for the analysis of surfactants on the synthesis of bismuth molybdate, affecting the structure and properties, using different surfactants, Bi_2MoO_6 nanosheets were prepared by hydrothermal method. The optimization of different kinds of surfactants (CTAB, KBr, PVP, PEG) effect on Bi_2MoO_6 sheet structure. And discussed the growth mechanism, in which the CTAB can obtain uniform bismuth molybdate nano film. When CTAB=0.15g, the synthesis of nano film thickness is only 5 ~ 15nm, compared to the surface area of 20.551 m2/g. and bismuth molybdate nano powder, bismuth molybdate nano sheet CTAB assisted preparation has stronger optical absorption band the width of low and better photocatalytic activity, 3 h after irradiation, methylene blue (MB) degradation rate of 81%. with CTAB as surfactant, using ethylene glycol / water mixed solvent thermal method to synthesize flower like Bi_2MoO_6 microspheres.Bi_2MoO_6 micron. The ball is made by the thickness of 10~20 mm nanosheets assembled. By changing the mixed solvent ratio morphology and size control can be achieved Bi_2MoO_6 microspheres, analyzed the growth mechanism of.EG:H2O=8:2 flower like microspheres, Bi_2MoO_6 flower like hollow structure synthesis has better photocatalytic activity than thin and flower clusters of micron the ball, 3 h after irradiation, the degradation rate of MB to 98%. of the mixed solvent thermal method based on respectively by one-step solvothermal method and Photoluminescence of Ag/Bi_2MoO_6 nanocomposites synthesized Ag load reduction method. The results showed that by one-step solvothermal method for preparation of hollow spherical Ag/Bi_2MoO_6 (Ag=6wt%) is the light induced reduction the samples prepared by band gap is narrower, so it has better absorption of visible light, on this basis to further explore the growth mechanism of hollow spheres by one step. The solvothermal samples for Ag/Bi_2MoO_6 The photocatalyst, after 3 h of irradiation, the degradation rate of MB to 90.2%. mixed solvothermal method based on micro sphere Bi2S3/Bi_2MoO_6 nanorods composite structure prepared by one-step solvothermal method. In this structure, the photogenerated electrons can be formed in the Bi2S3 and Bi_2MoO_6 interface transmission, so that the photogenerated electron hole pairs can be obtained effective separation, improve the migration rate of carrier. The photocatalytic properties of Bi2S3/Bi_2MoO_6 composite prepared under the same conditions was better than that of Bi_2MoO_6 microspheres prepared by the 3 h after irradiation, the degradation rate of MB reached 83%.

【學(xué)位授予單位】：西安科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TQ135.32;TB383.1

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