本文關(guān)鍵詞：BiOI的形貌調(diào)控、貴金屬負(fù)載及其光催化活性　出處：《淮北師范大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 半導(dǎo)體光催化 BiOI 形貌調(diào)控 光催化活性

【摘要】：近年來，半導(dǎo)體光催化在環(huán)境污染治理方面獲得了廣泛的關(guān)注。作為新型的半導(dǎo)體光催化劑BiOI，因其特殊的層狀結(jié)構(gòu)帶來的良好光催化性能，使其成為具有應(yīng)用潛力的對象之一。但是由于BiOI較窄的禁帶寬度（~1.75eV），使得光生電子-空穴對容易復(fù)合，大大降低了其光催化效率。因此，本論文旨在對BiOI進(jìn)行形貌調(diào)控和貴金屬負(fù)載，設(shè)計(jì)具有高活性的BiOI光催化劑，并通過系統(tǒng)的表征手段研究其光催化性能增強(qiáng)機(jī)制。 主要研究內(nèi)容和結(jié)論如下： （1）通過室溫直接水解法合成了一系列不同尺寸的二維片狀BiOI。KI溶液的體積和濃度之間的協(xié)同效應(yīng)顯著影響了片狀BiOI的尺寸和分散性。XRD結(jié)果分析表明，所有的BiOI樣品均為結(jié)晶性較好的四方晶系。在可見光下（λ400nm），，通過甲基橙的降解評價(jià)了BiOI樣品的光催化活性。結(jié)果表明，當(dāng)KI溶液濃度為0.035mol/L時(shí)，所制備的BiOI具有最佳的光催化性能，甲基橙的降解率達(dá)到92.6%。本實(shí)驗(yàn)為獲得高活性的片狀BiOI光催化劑提供了簡單的制備策略，可用于去除污水中的有機(jī)污染物。 （2）室溫條件下，利用乙二醇輔助水解法制備了分等級結(jié)構(gòu)的三維花狀BiOI光催化劑。表征并分析了BiOI樣品的形貌、元素組成、晶體相結(jié)構(gòu)和光學(xué)特征。結(jié)果表明，乙二醇的濃度大小是調(diào)控BiOI樣品形貌的主要因素。在可見光下（λ400nm），花狀結(jié)構(gòu)的BiOI(S10)在降解甲基橙的實(shí)驗(yàn)中表現(xiàn)出最佳的光催化活性，所對應(yīng)的準(zhǔn)一級速率常數(shù)為0.826h-1。BiOI樣品光催化活性的變化趨勢與光電流性能相一致。本實(shí)驗(yàn)為制備光催化性能優(yōu)異的三維花狀BiOI提供了有益參考。 （3）分別以二維片狀和三維花狀BiOI為載體，通過簡單的光沉積法合成了Ag/BiOI復(fù)合光催化劑。闡述了兩種形貌的BiOI載體對Ag量子點(diǎn)的生長過程及其Ag/BiOI光催化活性的影響。在光沉積過程中，二維片狀BiOI具有較弱的載流子分離效率，促進(jìn)了較大尺寸的Ag量子點(diǎn)生成，導(dǎo)致光生電子捕獲效率提高，光催化活性顯著增強(qiáng)。相比之下，三維花狀BiOI表面的Ag量子點(diǎn)尺寸較小，對應(yīng)的Ag/BiOI光催化活性增強(qiáng)較低。在降解甲基橙實(shí)驗(yàn)中，片狀和花狀BiOI的準(zhǔn)一級速率常數(shù)分別為0.32和0.85h-1，Ag/BiOI的光催化活性分別是對應(yīng)BiOI的3.25和1.11倍。在降解苯酚時(shí)，Ag/BiOI的光催化活性分別是對應(yīng)BiOI的1.31和1.13倍。以上結(jié)果表明，調(diào)控載體形貌是改善Ag/BiOI以至更廣泛的貴金屬/半導(dǎo)體復(fù)合物光催化活性的有效手段。
[Abstract]:In recent years, semiconductor photocatalysis has been widely concerned in environmental pollution control. As a semiconductor photocatalyst BiOI model, good photocatalytic properties due to its special layered structure, making it one of the objects with potential applications. But because of the narrow band gap of BiOI (~1.75eV), the photogenerated electrons - hole on the composite, and greatly reduce the photocatalytic efficiency. Therefore, this paper aims at the BiOI morphology control and noble metal loading, BiOI optical design of catalyst with high activity, and characterized by means of the research on its photocatalytic performance enhancement mechanism.
The main contents and conclusions are as follows:
(1) at room temperature by the direct hydrolysis of the synthesis of synergistic effect between volume and concentration of a series of different size of the two-dimensional sheet of BiOI.KI solution significantly affected the size and dispersion of flake BiOI.XRD results showed that all the BiOI samples are well crystallized in tetragonal system. Under visible light (lambda 400nm) BiOI, the photocatalytic activity of samples was evaluated by the degradation of methyl orange. The results showed that when the concentration of KI was 0.035mol/L, the prepared BiOI has the best photocatalytic performance, the degradation rate of methyl orange can reach 92.6%. in this experiment in order to obtain flake BiOI photocatalyst with high activity provides a strategy of simple preparation, can for removing the organic pollutant in the wastewater.
(2) under the condition of room temperature, 3D flower like hierarchical structure of BiOI photocatalyst prepared by ethylene glycol assisted hydrolysis method. Characterization and morphology of the samples, BiOI analysis of elements, crystal structure and optical characteristics. The results showed that the concentration of ethylene glycol is the main factor to regulate the morphology of BiOI samples in the visible. Light (2 400nm), flower like structure of BiOI (S10) showed the best photocatalytic activity in degradation of methyl orange in the experiment, consistent change trend and the photocurrent properties corresponding to the first-order rate constant of 0.826h-1.BiOI photocatalytic activity. This experiment provides a useful reference for the preparation of three-dimensional flower BiOI excellent photocatalytic performance.
(3) in two-dimensional sheet and 3D flower like BiOI as the carrier, the Ag/BiOI composite photocatalyst was prepared by photodeposition. Simple BiOI vector describes the influence of two kinds of morphologies on the growth process of Ag QDs and its photocatalytic activity of Ag/BiOI. In the light of the deposition process, two-dimensional sheet carrier BiOI has weak the separation efficiency, promote the generation of larger size Ag quantum dots, which leads to the photoinduced electron capture efficiency, the photocatalytic activity was significantly enhanced. In contrast, Ag small quantum dot 3D flowerlike BiOI surface, the photocatalytic activity of Ag/BiOI was lower. The corresponding enhancement in the degradation of methyl orange in the experiment, the pseudo first order rate constant flake like and flower like BiOI were 0.32 and 0.85h-1, respectively. The photocatalytic activity of Ag/BiOI is corresponding to BiOI 3.25 and 1.11 times. In the degradation of phenol, the photocatalytic activity of Ag/BiOI were 1.31 and 1.13 times of the corresponding BiOI. The results show that the regulation of the morphology of the carrier is an effective means to improve the photocatalytic activity of Ag/BiOI and even more precious metal / semiconductor complexes.

【學(xué)位授予單位】：淮北師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X505;O643.36

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 Haili Lin;Chunchun Zhou;Jing Cao;Shifu Chen;;Ethylene glycol-assisted synthesis, photoelectrochemical and photocatalytic properties of BiOI microflowers[J];Chinese Science Bulletin;2014年27期

本文編號：1407414