本文選題：碳點(diǎn)　切入點(diǎn)：有機(jī)染料　出處：《江蘇大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：抗生素和有機(jī)染料的大規(guī)模使用,給人類的生產(chǎn)和生活帶來(lái)極大便利的同時(shí),對(duì)生態(tài)環(huán)境和人類健康也構(gòu)成了嚴(yán)重威脅。傳統(tǒng)的污水處理技術(shù)無(wú)法實(shí)現(xiàn)有機(jī)分子的高效去除,相比之下,光催化氧化技術(shù)在有機(jī)染料、醫(yī)療廢水凈化中具有潛在的應(yīng)用前景。但光催化材料普遍存在光響應(yīng)范圍窄、光生電子-空穴對(duì)易復(fù)合導(dǎo)致的光催化效率低等諸多問題,這嚴(yán)重制約了光催化技術(shù)的推廣應(yīng)用。目前研究較為廣泛的光催化劑大多僅能響應(yīng)紫外光或可見光。為了拓寬光吸收范圍,近幾年碳點(diǎn)復(fù)合光催化劑逐漸發(fā)展起來(lái)。碳點(diǎn)具有獨(dú)特的光學(xué)性質(zhì)優(yōu)勢(shì),尺寸僅為幾納米,量子限域效應(yīng)使得其尺寸與光學(xué)性質(zhì)相關(guān)聯(lián)且可調(diào)。本文針對(duì)碳點(diǎn)復(fù)合光催化劑,圍繞光生電子的矢量轉(zhuǎn)移設(shè)計(jì)、界面修飾和實(shí)現(xiàn)紅外光的催化應(yīng)用等問題開發(fā)了一系列碳量子點(diǎn)復(fù)合光催化劑,并從組分調(diào)控、表面包覆、助催化劑負(fù)載和異質(zhì)結(jié)構(gòu)筑等方面探究了該體系的光催化降解速率和機(jī)理,優(yōu)化了碳點(diǎn)復(fù)合材料性能和反應(yīng)條件,為實(shí)現(xiàn)工業(yè)化應(yīng)用奠定了基礎(chǔ)。本文的主要研究?jī)?nèi)容如下:(1)通過(guò)濕化學(xué)法合成CQDs/Ag_2O復(fù)合材料,隨后通過(guò)NaBH4還原法在CQDs層表面沉積Ag納米粒子合成了CQDs/Ag/Ag_2O表面等離子體復(fù)合催化劑。CQDs在催化劑中作為介質(zhì)存在,與Ag_2O和Ag納米顆粒均存在強(qiáng)烈的化學(xué)鍵,這有利于光生載流子的有效轉(zhuǎn)移和分離。與光致還原法相比,NaBH4原位還原Ag納米粒子的合成方法簡(jiǎn)單、快速,并且不需要任何額外的光致還原設(shè)備,有利于大批量合成其它負(fù)載Ag納米單質(zhì)的銀鹽基復(fù)合材料。CQDs/Ag/Ag_2O復(fù)合催化劑具有全光譜催化活性,首先Ag粒子的Plasmon效應(yīng)有利于可見光的吸收,同時(shí),碳點(diǎn)的上轉(zhuǎn)換熒光效應(yīng)能將紅外光轉(zhuǎn)換為高能量光子,從而實(shí)現(xiàn)紅外光催化。實(shí)驗(yàn)結(jié)果表明,所制備的復(fù)合光催化劑的催化活性和穩(wěn)定性能均顯著增強(qiáng)是由CQDs包覆以及Ag顆粒的成功負(fù)載等協(xié)同效應(yīng)所導(dǎo)致。(2)用氫氣退火對(duì)TiO_2進(jìn)行改性,制備了氫化TiO_2納米帶(H-TiO_2),并研究了可見光催化性能。通過(guò)水熱合成法構(gòu)建了CDs/MoS_2@H-TiO_2核(H-TiO_2)殼(CDs/MoS_2)結(jié)構(gòu)復(fù)合材料。H-TiO_2納米帶的氧缺陷有利于促進(jìn)可見光的吸收,MoS_2和H-TiO_2之間異質(zhì)結(jié)的形成有利于光生電子的傳遞。同時(shí),MoS_2表面負(fù)載的碳點(diǎn)具有熒光和光致電子轉(zhuǎn)移性質(zhì),不僅使CDs/MoS_2@H-TiO_2復(fù)合物能夠吸收近紅外進(jìn)行光催化,而且能促進(jìn)躍遷到MoS_2導(dǎo)帶上的電子的進(jìn)一步躍遷,極大地抑制了光生電子空穴對(duì)的復(fù)合。(3)利用水熱合成法制備碳點(diǎn),以三聚氰胺為原料在550℃下熱解制備氮化碳(g-C_3N_4),隨后進(jìn)一步通過(guò)水熱合成法制得CDs/g-C_3N_4復(fù)合催化劑。將其分散在不同有機(jī)污染物中,在光照下評(píng)估其光催化降解速率。通過(guò)SEM、XRD、UV-Vis和EIS等基礎(chǔ)表征手段研究復(fù)合催化劑的基本性質(zhì)。研究表明,在g-C_3N_4的基礎(chǔ)上負(fù)載CDs可能引入了自帶帶隙(sub-band gap),增強(qiáng)對(duì)光譜的吸收范圍,最大吸收波長(zhǎng)可以達(dá)到620 nm,這意味著可以更加有效地利用低能光子。實(shí)驗(yàn)結(jié)果顯示,在0.50 wt%CDs/g-C_3N_4的光催化作用下,有機(jī)分子(RhB、MB、MO、TC、CIP)均可以得到有效的去除。
[Abstract]:The large-scale use of antibiotics and organic dyes, brings great convenience to people's production and life at the same time, the ecological environment and human health also pose a serious threat. The traditional wastewater treatment process to achieve efficient removal of organic molecules, in contrast, the photocatalytic oxidation technology in organic dye wastewater purification, medical application potential. But photocatalytic materials generally narrow light response range, the photogenerated electron hole pairs to many problems caused by the low efficiency of photocatalytic composite, which seriously restricted the application of photocatalytic technology. The photocatalyst is widely studied mostly only in response to ultraviolet or visible light. In order to broaden the range of light absorption in recent years, carbon composite photocatalyst carbon has developed gradually. The optical properties of the unique advantages, the size of only a few nanometers, quantum confinement effect due to its size and The optical properties associated with adjustable. The carbon composite photocatalyst, photoinduced electron transfer around the vector design, interface modification and implementation of a series of catalytic applications of infrared carbon quantum dots composite photocatalyst was developed, and the control group, the surface coating, catalyst loading and heterogeneous structure etc. on the rate of photocatalytic degradation and the mechanism of the system, carbon composites properties and reaction conditions were optimized, which laid the foundation for the realization of industrial application. The main contents of this paper are as follows: (1) a CQDs/Ag_2O composite material by wet chemical method, then deposited on the surface of the CQDs layer of Ag nanoparticles were synthesized by surface plasmon CQDs/Ag/Ag_2O the.CQDs complex catalyst in the catalyst as a medium by NaBH4 reduction method, there were strong chemical bonds with Ag_2O and Ag nano particles, which is conducive to the photocarrier The effective transfer and separation. Compared with light induced reduction method, the synthesis method of NaBH4 in situ reduction of Ag nanoparticles is simple, fast, and does not require any additional light induced reduction equipment, suitable for large scale synthesis of silver base composite material.CQDs/Ag/Ag_2O composite catalyst Ag loaded with other nano elemental full spectrum catalytic activity, Plasmon first Ag effect the particle is conducive to the absorption of visible light, at the same time, the carbon upconversion effect can be converted to a high energy photon infrared light, infrared light to achieve catalysis. The experimental results show that the catalytic activity of the composite photocatalyst and preparation stability was significantly enhanced by CQDs coated Ag particles and successfully loaded together the effect of the cause. (2) TiO_2 was modified by hydrogen annealing, preparation of hydrogenated TiO_2 nanoribbons (H-TiO_2), and to study the photocatalytic properties through hydrothermal synthesis. The construction of CDs/MoS_2@H-TiO_2 core (H-TiO_2) shell (CDs/MoS_2) oxygen defect structure of composite material of.H-TiO_2 nanobelts is conducive to the absorption of visible light, between MoS_2 and H-TiO_2 heterojunction is conducive to the formation of photoinduced electron transfer. At the same time, the surface of MoS_2 loaded carbon with fluorescence and photoinduced electron transfer properties, not only the CDs/MoS_2@H-TiO_2 complexes can absorb near-infrared light catalysis, but also can accelerate the transition to further transition electron conduction band of MoS_2 on, greatly inhibited the photogenerated electron hole pair recombination. (3) were synthesized by using hydrothermal carbon materials, under the temperature of 550 DEG C prepared by pyrolysis of carbon nitride (using melamine as g-C_3N_4), then through the hydrothermal synthesis of CDs/g-C_3N_4 composite catalyst. The dispersed in different organic pollutants, evaluate the photocatalytic degradation rate under light. Through SEM, XRD, UV-Vis and EI The basic properties of S based composite catalyst characterization. The results show that, on the basis of the g-C_3N_4 load CDs likely introduced with the band gap (sub-band gap), enhanced absorption range of the spectrum, the maximum absorption wavelength can reach 620 nm, which means that we can more effectively use low energy photons. Experimental results show that the photocatalytic effect of 0.50 wt%CDs/g-C_3N_4, organic molecules (RhB, MB, MO, TC, CIP) can be effectively removed.

【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O643.36

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相關(guān)期刊論文 前1條

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本文編號(hào)：1566132