本文選題：類石墨碳化氮 + 一步法�。� 參考：《江蘇大學(xué)》2017年碩士論文

【摘要】：隨著科學(xué)技術(shù)的進步和發(fā)展,給人類社會帶來越來越多的便利,但是同時也帶來一些負面影響。尤其是在最近今年,隨著工業(yè)發(fā)展,全球化能源危機和環(huán)境污染問題嚴重影響我們的生活和身體健康。其中最嚴峻的就是石油、煤炭等化石燃料的過度消耗致使能源危機加重,另一方面則是化石燃料使用過程中會產(chǎn)生二次污染加劇環(huán)境污染問題。因此尋找一種高效、環(huán)保的新能源可以從根本上解決目前的全球性問題。自1972年日本科學(xué)家發(fā)現(xiàn)TiO2在紫外光下可以分解水產(chǎn)氫后,利用光催化技術(shù)進行光分解水產(chǎn)氫被認為是解決上述問題最佳手段。但是,傳統(tǒng)光催化劑由于一些自身的缺陷導(dǎo)致無法滿足科學(xué)家的要求,因此尋找一種新型光催化劑是目前將光催化技術(shù)進行實際應(yīng)用的關(guān)鍵。近幾年,一種類石墨相g-C_3N_4光催化劑引起各國科學(xué)家的關(guān)注,由于其具有較窄禁帶寬度(2.7 eV)、合適的價導(dǎo)帶位置可以在可見光下進行分解水產(chǎn)氫;另一方面g-C_3N_4的合成方法簡單、合成原料較廣可以進行大規(guī)模生產(chǎn)令其成為光催化領(lǐng)域研究的熱點。然而,純相的g-C_3N_4的自身電荷與空穴的分離率較低嚴重抑制其光催化性能。本文根據(jù)g-C_3N_4的自身缺點,通過一步法合成Ag量子點/g-C_3N_4復(fù)合催化劑、原位生長法合成CuS/g-C_3N_4復(fù)合光催化劑提高g-C_3N_4的電子與空穴的分離率進而增強光催化性能;將g-C_3N_4制備成量子點與SnNb_2O_6提高太陽光利用率,進而提高產(chǎn)氫性能,并對g-C_3N_4進行進一步的研究。本文的重點研究有一下幾點:(1)利用一步法合成Ag QDs/g-C_3N_4復(fù)合光催化劑,簡化光催化劑的制備過程。通過一系列表征發(fā)現(xiàn),Ag量子點的等離子共振作用可以有效提高催化劑對于可見光的吸收強度,有利于對于太陽光的利用率;另一方面,Ag量子點可以作為助催化劑提高光催化劑的電子與空穴的分離率。我們通過分解水產(chǎn)氫實驗發(fā)現(xiàn)復(fù)合光催化劑的產(chǎn)氫性能得到極大提高。(2)利用原位生長法合成新型光催化劑CuS/g-C_3N_4,在可見光下,通過界面電子轉(zhuǎn)移,g-C_3N_4價帶上的被激發(fā)的電子可以直接轉(zhuǎn)移到CuS納米粒子,部分CuS被還原為Cu2S,CuS/Cu2S納米簇可以有效捕獲激發(fā)電子,防止電子與空穴的復(fù)合,提高光催化活性,Cus/g-C_3N_4在產(chǎn)氫實驗中表現(xiàn)出高效產(chǎn)氫性能和的良好的穩(wěn)定性。(3)通過水熱法合成CNQDs/SnNb_2O_6光催化劑,CNQDs既可以作為助催化劑捕獲被激發(fā)的電子并在助催化劑表面參與產(chǎn)氫過程,另一方面,CNQDs具有上轉(zhuǎn)換效應(yīng),可以將長波長的光轉(zhuǎn)換為短波長的光被純SnNb_2O_6多利用,激發(fā)更多的電子參與光催化反應(yīng),進而提高光催化性能。
[Abstract]:With the progress and development of science and technology, it brings more and more convenience to human society, but also brings some negative effects. Especially this year, with the development of industry, global energy crisis and environmental pollution have seriously affected our lives and health. The most severe is the excessive consumption of fossil fuels such as oil and coal, which makes the energy crisis worse. On the other hand, the secondary pollution in the use of fossil fuels will aggravate the environmental pollution problem. Therefore, looking for an efficient and environmentally-friendly new energy can fundamentally solve the current global problems. Since Japanese scientists discovered in 1972 that TiO2 can decompose aquatic hydrogen under ultraviolet light, photocatalytic technology is considered to be the best way to solve the above problems. However, the traditional photocatalyst can not meet the requirements of scientists due to its own defects, so finding a new photocatalyst is the key to the practical application of photocatalytic technology. In recent years, a kind of graphite phase g-C_3N_4 photocatalyst has attracted the attention of scientists all over the world. Due to its narrow band gap of 2.7 EV, the suitable valence band position can be used to decompose aquatic hydrogen under visible light. On the other hand, the synthetic method of g-C_3N_4 is simple. The wide range of synthetic raw materials can be used in mass production, so it has become a hot spot in the field of photocatalysis. However, the photocatalytic activity of pure phase g-C_3N_4 is seriously inhibited by the low separation rate of its own charge and hole. According to the shortcomings of g-C_3N_4, Ag quantum dots / g-C _ 3N _ 4 composite catalysts were synthesized by one-step method, and CuS/g-C_3N_4 composite photocatalysts were synthesized by in-situ growth method to improve the separation rate of electrons and holes of g-C_3N_4 and thus enhance its photocatalytic performance. Quantum dots (QDs) prepared by g-C_3N_4 and SnNb_2O_6 were used to improve the utilization of solar light and hydrogen production. The further study of g-C_3N_4 was carried out. This paper focuses on the following points: 1) Synthesis of Ag QDs/g-C_3N_4 composite photocatalyst by one-step method to simplify the preparation process of photocatalyst. Through a series of characterization, it is found that the plasmon resonance of Ag quantum dots can effectively increase the absorption intensity of visible light of the catalyst, and is beneficial to the utilization of solar light. On the other hand, Ag quantum dots can be used as cocatalyst to improve the separation efficiency of electron and hole in photocatalyst. We found that the hydrogen production performance of the composite photocatalyst has been greatly improved by the experiment of decomposing aquatic hydrogen. (2) A new photocatalyst, CuS / g-C _ 3N _ 4, was synthesized by in-situ growth method. Through the interfacial electron transfer, the excited electrons in the valence band of Mr _ 3N _ 4 can be transferred directly to the CuS nanoparticles, and some of the CuS can be reduced to Cu _ 2S / Cu _ S / Cu _ 2S nanoclusters, which can effectively capture the excited electrons and prevent the recombination of electrons and holes. In the hydrogen production experiment, Cus / g-C _ 3N _ 4 showed high hydrogen production performance and good stability. The photocatalyst can be used as a co-catalyst to capture the excited electrons and participate in the hydrogen production process on the surface of the co-catalyst. On the other hand, CNQDs have upconversion effect, which can convert long wavelength light to short wavelength light and be used by pure SnNb_2O_6 to stimulate more electrons to participate in photocatalytic reaction, thus improving photocatalytic performance.
【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】：O643.36;TQ116.2

【參考文獻】

相關(guān)期刊論文 前1條

1 王西峰;胡曉蓮;龔昕;班云霄;;UV-TiO_2 photocatalytic disinfection and photoreactivation of pathogenic bacterium in municipal wastewater[J];Journal of Central South University;2016年12期

，

本文編號：1852826