Ta基復(fù)合光催化劑的制備及其性能改性的研究
發(fā)布時(shí)間：2018-07-16 12:54
【摘要】：半導(dǎo)體光催化技術(shù)是一種有前途的方式,能有效地轉(zhuǎn)化太陽能解決加劇的能源短缺和水污染問題,其中,最關(guān)鍵的技術(shù)就是開發(fā)和利用環(huán)保、高效的半導(dǎo)體光催化劑。因此,設(shè)計(jì)和構(gòu)建新型、環(huán)保的光催化劑將成為解決環(huán)境水污染問題的重要研究方向�；赥a基半導(dǎo)體(Ta_2O_5、Ta_3N_5)豐富的電子結(jié)構(gòu)、良好的物理化學(xué)特性和光催化性能等,在光催化領(lǐng)域有很好的應(yīng)用前景。然而,Ta基半導(dǎo)體的帶隙寬、不穩(wěn)定、光吸收能力差等自身缺陷限制了其光催化性能,無法廣泛應(yīng)用到實(shí)際中。因而,本論文旨提高Ta基單體光催化材料的催化性能及其在可見光下的應(yīng)用,主要設(shè)想對Ta基光催化劑(Ta_2O_5、Ta_3N_5)與其他帶隙匹配的半導(dǎo)體復(fù)合,研究Ta基材料與其它半導(dǎo)體的復(fù)合界面和協(xié)同效應(yīng),并系統(tǒng)地評價(jià)復(fù)合物降解水體污染物的催化活性和穩(wěn)定性,探討該Ta基復(fù)合光催化劑的界面電荷傳輸機(jī)理和光催化污染物的降解機(jī)制。本論文主要的研究內(nèi)容和結(jié)果如下:(1)首次通過簡便的超聲分散法成功合成了無定型Ta_2O_5/g-C_3N_4納米片,結(jié)構(gòu)測試表明無定型的Ta_2O_5均勻分散在g-C_3N_4表面上,從而形成緊密接觸的界面。在可見光照射下,相對于無定型Ta_2O_5和g-C_3N_4單體,無定型Ta_2O_5/g-C_3N_4復(fù)合物在催化降解RhB時(shí)展現(xiàn)了較高的光催化活性。當(dāng)無定型Ta_2O_5質(zhì)量比為3%時(shí),Ta_2O_5/g-C_3N_4復(fù)合光催化劑擁有最佳的光催化活性(99.14%),降解速率常數(shù)是2.0055 h-1,分別是單體Ta_2O_5和g-C_3N_4的6.2和14.9倍。光催化循環(huán)實(shí)驗(yàn)表明:復(fù)合光催化劑具有較高的光穩(wěn)定性,因而該Ta基復(fù)合樣品是良好的可重復(fù)使用性的。更有趣地是,無定型Ta_2O_5/g-C_3N_4納米片雜化物的活性更優(yōu)異于晶型Ta_2O_5/g-C_3N_4。復(fù)合光催劑光催化活性的大大提高主要?dú)w因于協(xié)同效應(yīng),包括高比表面積、增強(qiáng)的可見光吸收、有效的界面電荷轉(zhuǎn)移和降低的電荷重組率。在捕獲結(jié)果的基礎(chǔ)上試探性地提出了合理的可見光降解機(jī)理。(2)采用簡單浸漬法合成新型的Ta_3N_5/g-C_3N_4金屬/非金屬氮化雜化物,以羅丹明B(RhB)為目標(biāo)污染物,在可見光下對該雜化物光催化活性的評價(jià),結(jié)果顯示:Ta_3N_5/g-C_3N_4材料的光催化活性遠(yuǎn)遠(yuǎn)高于單體g-C_3N_4的催化活性。當(dāng)Ta_3N_5與g-C_3N_4質(zhì)量比為0.02:1時(shí),Ta_3N_5/g-C_3N_4雜化樣品擁有最高的光催化效率,其降解速率常數(shù)是g-C_3N_4的2.71倍。Ta_3N_5/g-C_3N_4金屬/非金屬氮化雜化物性能提高主要可歸因于Ta_3N_5和g-C_3N_4間的協(xié)同作用,拓寬了可見光吸收的范圍,提高光生電子和空穴的有效分離速率。另外,該雜化氮化物展現(xiàn)了優(yōu)異的光穩(wěn)定性和可重復(fù)利用性。自由捕獲實(shí)驗(yàn)表明光生h+和·OH是無定型Ta_2O_5/g-C_3N_4復(fù)合物光催化降解反應(yīng)中的主要活性物質(zhì)。(3)通過簡單的水熱法成功合成了新型Z型Ta_3N_5納米粒子/銳鈦礦TiO_2空心球復(fù)合光催化劑。詳細(xì)研究了Ta_3N_5/TiO_2空心球復(fù)合物的形態(tài)、光學(xué)和光催化特性。有趣的是,當(dāng)Ta_3N_5納米粒子和TiO_2空心球耦合,明顯拓寬了太陽光的響應(yīng)范圍,提高了降解左氧氟沙星(LEV)的光催化活性。特別地,和單體空心球TiO_2的活性(79.18%)相比,3-Ta_3N_5/TiO_2復(fù)合材料不僅擁有穩(wěn)定、可回收利用的特性,還具有高的LEV光降解活性(97.12%),這可能是因?yàn)閮烧叩膮f(xié)同效應(yīng),介孔表面和有效的電荷傳輸性能所致。根據(jù)捕獲實(shí)驗(yàn)和光電流分析,提出了的Z型半導(dǎo)體降解機(jī)理。
[Abstract]:Semiconductor photocatalytic technology is a promising way to effectively transform solar energy to solve the problem of energy shortage and water pollution. The key technology is to develop and utilize the environmentally friendly and efficient semiconductor photocatalyst. Therefore, the design and construction of a new type of ring protected photocatalyst will be a solution to the environmental water pollution problem. Based on the rich electronic structure of Ta based semiconductor (Ta_2O_5, Ta_3N_5), good physical and chemical properties and photocatalytic properties, it has a good application prospect in the field of photocatalysis. However, the self physical defects such as wide band gap, instability and poor optical absorption capacity of Ta based semiconductors can not be widely applied to the solid. Therefore, the purpose of this thesis is to improve the catalytic properties of Ta based monomers and their applications in visible light. The main idea is to combine the Ta based Photocatalyst (Ta_2O_5, Ta_3N_5) with other bandgap semiconductors, to study the composite interface and synergistic effect of Ta based materials and other semiconductors, and to systematically evaluate the degradation of the complex body of water. The catalytic activity and stability of the pollutants are discussed and the mechanism of interface charge transfer and the degradation mechanism of photocatalytic pollutants of the Ta based composite photocatalyst are discussed. The main contents and results of this paper are as follows: (1) the amorphous Ta_2O_5/g-C_3N_4 nanoscale was successfully synthesized by a simple ultrasonic dispersion method for the first time, and the structure test showed the amorphous T A_2O_5 is uniformly dispersed on the surface of g-C_3N_4 to form a close contact interface. Under visible light, the amorphous Ta_2O_5/g-C_3N_4 complex exhibits higher photocatalytic activity than the amorphous Ta_2O_5 and g-C_3N_4 monomer in the catalytic degradation of RhB. When the amorphous Ta_2O_5 mass ratio is 3%, the Ta_2O_5/g-C_3N_4 composite photocatalyst is used. With the best photocatalytic activity (99.14%), the rate constant of the degradation is 2.0055 H-1, which is 6.2 and 14.9 times of the monomer Ta_2O_5 and g-C_3N_4 respectively. The photocatalytic cycle experiment shows that the composite photocatalyst has high photostability, so the Ta based composite sample is well reusable. More interestingly, the amorphous Ta_2O_5/g-C_3N_4 Na The activity of the rice hybrids is better than that of the crystalline Ta_2O_5/g-C_3N_4. composite photocatalyst, which is largely attributed to the synergistic effect, including high specific surface area, enhanced visible light absorption, effective interface charge transfer and reduced charge recombination rate. Photodegradation mechanism (2) a new type of Ta_3N_5/g-C_3N_4 metal / nonmetallic nitrided hybrid was synthesized by simple impregnation. The photocatalytic activity of the hybrid was evaluated under visible light with Luo Danming B (RhB) as the target pollutant. The results showed that the photochemical activity of the Ta_3N_5/g-C_3N_4 material was much higher than that of the monomer g-C_3N_4. When Ta_3N_ When the mass ratio of 5 to g-C_3N_4 is 0.02:1, the Ta_3N_5/g-C_3N_4 hybrid sample has the highest photocatalytic efficiency. The degradation rate constant is 2.71 times of g-C_3N_4 and the performance of.Ta_3N_5/g-C_3N_4 metal / non-metallic nitrided hybrids is mainly attributable to the synergism between Ta_3N_5 and g-C_3N_4, which widens the range of visible light absorption and improves the light generating electricity. In addition, the hybrid nitrogen compounds exhibit excellent light stability and reproducibility. Free capture experiments show that h+ and. OH are the main active substances in the photocatalytic degradation of amorphous Ta_2O_5/g-C_3N_4 complexes. (3) a new Z type Ta_3N_5 nanometer was successfully synthesized by a simple hydrothermal method. Particle / anatase TiO_2 hollow sphere composite photocatalyst. The morphology, optical and photocatalytic properties of the Ta_3N_5/TiO_2 hollow sphere complex are studied in detail. It is interesting that the coupling of Ta_3N_5 nanoparticles and TiO_2 hollow spheres greatly widens the response range of the solar light and improves the photocatalytic activity of the degradation of levofloxacin (LEV). Compared with the activity of the body hollow sphere TiO_2 (79.18%), the 3-Ta_3N_5/TiO_2 composites not only have stable, recyclable properties, but also have high LEV photodegradation activity (97.12%), which may be due to the synergistic effect of both, mesoporous surface and effective charge transmission properties. According to the capture experiment and photocurrent analysis, the Z half is proposed. The mechanism of conductor degradation.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O643.36
本文編號(hào)：2126454
[Abstract]:Semiconductor photocatalytic technology is a promising way to effectively transform solar energy to solve the problem of energy shortage and water pollution. The key technology is to develop and utilize the environmentally friendly and efficient semiconductor photocatalyst. Therefore, the design and construction of a new type of ring protected photocatalyst will be a solution to the environmental water pollution problem. Based on the rich electronic structure of Ta based semiconductor (Ta_2O_5, Ta_3N_5), good physical and chemical properties and photocatalytic properties, it has a good application prospect in the field of photocatalysis. However, the self physical defects such as wide band gap, instability and poor optical absorption capacity of Ta based semiconductors can not be widely applied to the solid. Therefore, the purpose of this thesis is to improve the catalytic properties of Ta based monomers and their applications in visible light. The main idea is to combine the Ta based Photocatalyst (Ta_2O_5, Ta_3N_5) with other bandgap semiconductors, to study the composite interface and synergistic effect of Ta based materials and other semiconductors, and to systematically evaluate the degradation of the complex body of water. The catalytic activity and stability of the pollutants are discussed and the mechanism of interface charge transfer and the degradation mechanism of photocatalytic pollutants of the Ta based composite photocatalyst are discussed. The main contents and results of this paper are as follows: (1) the amorphous Ta_2O_5/g-C_3N_4 nanoscale was successfully synthesized by a simple ultrasonic dispersion method for the first time, and the structure test showed the amorphous T A_2O_5 is uniformly dispersed on the surface of g-C_3N_4 to form a close contact interface. Under visible light, the amorphous Ta_2O_5/g-C_3N_4 complex exhibits higher photocatalytic activity than the amorphous Ta_2O_5 and g-C_3N_4 monomer in the catalytic degradation of RhB. When the amorphous Ta_2O_5 mass ratio is 3%, the Ta_2O_5/g-C_3N_4 composite photocatalyst is used. With the best photocatalytic activity (99.14%), the rate constant of the degradation is 2.0055 H-1, which is 6.2 and 14.9 times of the monomer Ta_2O_5 and g-C_3N_4 respectively. The photocatalytic cycle experiment shows that the composite photocatalyst has high photostability, so the Ta based composite sample is well reusable. More interestingly, the amorphous Ta_2O_5/g-C_3N_4 Na The activity of the rice hybrids is better than that of the crystalline Ta_2O_5/g-C_3N_4. composite photocatalyst, which is largely attributed to the synergistic effect, including high specific surface area, enhanced visible light absorption, effective interface charge transfer and reduced charge recombination rate. Photodegradation mechanism (2) a new type of Ta_3N_5/g-C_3N_4 metal / nonmetallic nitrided hybrid was synthesized by simple impregnation. The photocatalytic activity of the hybrid was evaluated under visible light with Luo Danming B (RhB) as the target pollutant. The results showed that the photochemical activity of the Ta_3N_5/g-C_3N_4 material was much higher than that of the monomer g-C_3N_4. When Ta_3N_ When the mass ratio of 5 to g-C_3N_4 is 0.02:1, the Ta_3N_5/g-C_3N_4 hybrid sample has the highest photocatalytic efficiency. The degradation rate constant is 2.71 times of g-C_3N_4 and the performance of.Ta_3N_5/g-C_3N_4 metal / non-metallic nitrided hybrids is mainly attributable to the synergism between Ta_3N_5 and g-C_3N_4, which widens the range of visible light absorption and improves the light generating electricity. In addition, the hybrid nitrogen compounds exhibit excellent light stability and reproducibility. Free capture experiments show that h+ and. OH are the main active substances in the photocatalytic degradation of amorphous Ta_2O_5/g-C_3N_4 complexes. (3) a new Z type Ta_3N_5 nanometer was successfully synthesized by a simple hydrothermal method. Particle / anatase TiO_2 hollow sphere composite photocatalyst. The morphology, optical and photocatalytic properties of the Ta_3N_5/TiO_2 hollow sphere complex are studied in detail. It is interesting that the coupling of Ta_3N_5 nanoparticles and TiO_2 hollow spheres greatly widens the response range of the solar light and improves the photocatalytic activity of the degradation of levofloxacin (LEV). Compared with the activity of the body hollow sphere TiO_2 (79.18%), the 3-Ta_3N_5/TiO_2 composites not only have stable, recyclable properties, but also have high LEV photodegradation activity (97.12%), which may be due to the synergistic effect of both, mesoporous surface and effective charge transmission properties. According to the capture experiment and photocurrent analysis, the Z half is proposed. The mechanism of conductor degradation.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O643.36
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