發(fā)布時(shí)間：2018-04-14 00:06

  本文選題：納米二氧化鈦 + 缺陷態(tài)　； 參考：《煙臺大學(xué)》2017年碩士論文

【摘要】：最近10年的研究發(fā)現(xiàn),帶隙缺陷態(tài)是影響納米結(jié)構(gòu)半導(dǎo)體光電化學(xué)性能的主要因素。然而,其影響機(jī)制尚不清晰。本文通過研究二氧化鈦納米結(jié)構(gòu)薄膜電極的缺陷態(tài)分布以及載流子動力學(xué)行為,進(jìn)而揭示帶隙缺陷態(tài)對光電催化水分解制氫活性的影響,并基于此指導(dǎo)制備高活性納米結(jié)構(gòu)二氧化鈦光電極薄膜。本文借助場發(fā)射掃描電子顯微鏡(FESEM)和X射線粉末衍射(XRD)技術(shù)對樣品的納米結(jié)構(gòu)和形態(tài)進(jìn)行研究;借助電化學(xué)交流阻抗譜(EIS)研究缺陷態(tài)對半導(dǎo)體載流子傳輸動力學(xué)行為的影響;借助循環(huán)伏安法(CV)以及斬光時(shí)間電流(I-t)曲線等光電化學(xué)測試技術(shù)研究樣品光電化學(xué)性質(zhì)及缺陷態(tài)分布情況,研究內(nèi)容主要分為以下三個(gè)部分:(1)探究二氧化鈦納米顆粒薄膜中的兩種常見的缺陷,即表面和晶界缺陷對光電催化活性的破壞作用。為此,我們采用兩種不同的燒結(jié)機(jī)制制備了納米聚集結(jié)構(gòu)相同但兩種缺陷含量不同的二氧化鈦薄膜。研究發(fā)現(xiàn)晶界缺陷對薄膜的光電化學(xué)性能影響更甚,是影響載流子傳輸動力學(xué)以及導(dǎo)致光電化學(xué)活性較低的主要原因。(2)在(1)的基礎(chǔ)上,深入探究缺陷態(tài)對半導(dǎo)體光電化學(xué)性質(zhì)的影響機(jī)制。研究發(fā)現(xiàn),缺陷態(tài)密度越大,光電流衰減越為嚴(yán)重。本章通過染料吸附、酚酞變色、“Ti-O-P”化學(xué)鍵遇堿水解以及電化學(xué)/光電化學(xué)等一系列實(shí)驗(yàn),證明被捕獲電子與電解質(zhì)陽離子間存在強(qiáng)的靜電吸引作用,導(dǎo)致電子逃逸勢壘增大,從而增加了光生載流子的傳輸阻力以及復(fù)合幾率,進(jìn)而引發(fā)光電流衰減。(3)基于(1)和(2),借助溶膠凝膠法與水熱法制備了單晶二氧化鈦納米棒陣列薄膜,并建立了高溫?zé)崽幚砀纳乒怆娀瘜W(xué)活性的方法。研究表明高溫?zé)Y(jié)可以顯著減少缺陷,從而優(yōu)化了載流子傳輸動力學(xué)。本文對揭示納米結(jié)構(gòu)半導(dǎo)體缺陷態(tài)對光電化學(xué)性質(zhì)的影響機(jī)制以及指導(dǎo)高活性半導(dǎo)體光催化劑和光電極的研制都具有一定的借鑒作用。
[Abstract]:In the last 10 years, it has been found that the band gap defect states are the main factors affecting the photochemical properties of nanostructured semiconductors.However, its influence mechanism is not clear.In this paper, the distribution of defect states and the carrier dynamics of TIO _ 2 nanostructured thin film electrodes are studied, and the effect of the defect states in band gap on the activity of photocatalytic water decomposition to produce hydrogen is revealed.Based on this guidance, highly active nanostructured TIO _ 2 photoelectrode films were prepared.In this paper, the nanostructures and morphology of the samples were studied by means of field emission scanning electron microscopy (FESEM) and X-ray powder diffraction (XRD) techniques, and the effects of defect states on the transport kinetics of semiconductor carriers were studied by electrochemical impedance spectroscopy (EIS).By means of cyclic voltammetry (CV) and chopping time current (I-t) curves, the photoelectric chemical properties and the distribution of defect states of the samples were studied.The research contents are divided into the following three parts: 1) to explore the destruction of photocatalytic activity caused by surface and grain boundary defects in TIO _ 2 nanocrystalline films.Therefore, two different sintering mechanisms were used to prepare TIO _ 2 thin films with the same nano-aggregate structure but different defect contents.It is found that grain boundary defects have a greater effect on the photochemical properties of the films, which is the main reason for the influence of carrier transport kinetics and the lower photochemical activity.The mechanism of the effect of defect states on the photochemical properties of semiconductors is studied in depth.It is found that the higher the density of defect states, the more serious the photocurrent attenuation.In this chapter, a series of experiments, such as dye adsorption, phenolphthalein coloration, "Ti-O-P" chemical bond hydrolysis and electrochemical / photochemistry, show that there is a strong electrostatic attraction between trapped electrons and electrolyte cations.The electron escape barrier increases, which increases the transport resistance and recombination probability of photogenerated carriers, and then leads to photocurrent attenuation. Based on 1) and 2 +, single crystal titanium dioxide nanorod array films are prepared by sol-gel method and hydrothermal method.The method of improving photochemical activity by high temperature heat treatment was established.The results show that high temperature sintering can significantly reduce defects and optimize carrier transport kinetics.This paper can be used for reference in revealing the influence mechanism of the defect states of nanostructured semiconductors on the photochemical properties and guiding the development of highly active semiconductor photocatalysts and photoelectrodes.
【學(xué)位授予單位】：煙臺大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TQ134.11;TB383.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 韓冬;何濤;徐金光;王，

本文編號：1746810