本文關(guān)鍵詞：一維二氧化鈦的制備及Ag、Au納米顆粒對其表面修飾　出處：《湖南大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 一維TiO_2納米材料 不同形貌 表面光伏特性 表面改性

【摘要】：納米TiO2是一種多功能半導(dǎo)體材料,因其具備強(qiáng)穩(wěn)定性,無毒,電子遷移率高等優(yōu)異特性,激起了研究者對其關(guān)注熱潮。目前的研究結(jié)果表明TiO2在光催化、光電轉(zhuǎn)換和紫外探測等領(lǐng)域均有廣闊的應(yīng)用前景。與其他TiO2粉體相比,一維納米材料的穩(wěn)定性更高,電荷傳輸能力更強(qiáng),比表面積更大,這有利于提高其光電性能。同時,納米材料的應(yīng)用也依賴于不同形貌所表現(xiàn)出來的特點(diǎn)。目前報道了許多用濕化學(xué)法制備TiO2的研究成果,但是由于金屬Ti的高熔點(diǎn)、低氣壓特性,很難在溫和條件下采用氣相法合成一維TiO2納米材料。本文采用一種經(jīng)濟(jì)、簡單的方法合成形貌各異的高結(jié)晶度一維TiO2納米結(jié)構(gòu),討論了不同形貌結(jié)構(gòu)的生長機(jī)理和光電性能,并對TiO2納米線的表面改性做初步研究,具體結(jié)果如下： (1)以Ti片為鈦源,Pd為催化劑,采用CVD法,在不同催化劑含量和反應(yīng)溫度下,制備出形貌各異的TiO2納米結(jié)構(gòu)。實(shí)驗(yàn)發(fā)現(xiàn),①Ti片在PdCl2：乙醇溶液中用紫外光照射30min、1h和2h,于900℃反應(yīng),得到的納米線尺寸從56.4nm增至187.95nm,長度從幾十微米減至幾微米。②保持催化劑濃度一定,反應(yīng)溫度為700℃、730℃和800℃,分別得到了TiO2納米片、納米帶和塔狀結(jié)構(gòu)。XRD和拉曼光譜表征證實(shí)所有的Ti02納米結(jié)構(gòu)都是純凈的金紅石型；納米線的形成為VLS生長機(jī)制,而納米片、納米帶和塔狀結(jié)構(gòu)則是VLS和VS共同作用的結(jié)果。 (2)催化劑處理1h,在760℃下反應(yīng)40min制備了帶鋸齒的錐狀TiO2納米帶。鋸齒的出現(xiàn)是納米帶在生長過程中,表面裸露的Ti+和O-的活性不同而引起生長速度不同形成的。單根納米帶的微區(qū)拉曼成像表明這種TiO2錐狀結(jié)構(gòu)的化學(xué)組分分布均勻,表面光伏測試中也表現(xiàn)了良好的光電響應(yīng),這對TiO2在光電器件方面的應(yīng)用具有重要價值。 (3)最后采用光化學(xué)沉積法和浸漬-沉積法分別合成Ag/TiO2和Au/TiO2復(fù)合結(jié)構(gòu)。比較了沉積不同時間的金屬顆粒沉積量,沉積時間越長,吸附于TiO2納米線表面的顆粒越多。當(dāng)Au顆粒吸附時間為12h時,其拉曼光譜在441cm-1處發(fā)生了藍(lán)移,這是由于過量的Au顆粒沉積在納米線表面,擠壓到TiO2的表面原子,使TiO2表面原子的相互作用力狀態(tài)發(fā)生了變化。表面光伏曲線表明吸附適量金屬顆粒的TiO2納米線的光吸收范圍有所拓寬,響應(yīng)強(qiáng)度增強(qiáng),說明金屬顆粒的表面修飾有利于提高其光電性能。
[Abstract]:Nano TiO2 is a kind of multifunctional semiconductor material, because of its strong stability, non-toxic, high electron mobility and excellent characteristics, aroused the researchers attention to the boom. The results indicated that the TiO2 in photocatalytic field has broad application prospects of photoelectric conversion and UV detection. Compared with other TiO2 powder body, stability of one-dimensional nano materials is higher, the charge transfer ability is stronger, bigger than the surface area, which is conducive to improve the photoelectric performance. At the same time, the application of nano materials is also dependent on the characteristics of different morphologies is shown. At present, many research results reported by the wet chemical synthesis of TiO2, but due to the high melting point metal Ti, low pressure characteristics, it is difficult to use the gas phase synthesis of one-dimensional TiO2 nanomaterials under mild conditions. This paper uses a simple method for the synthesis of economy, different morphologies of high crystallinity of one-dimensional TiO2 nanostructures, The growth mechanism and photoelectric properties of different morphologies are discussed, and the surface modification of TiO2 nanowires is preliminarily studied. The results are as follows:
(1) to Ti as titanium source, Pd as catalyst, using CVD method in different catalyst concentration and reaction temperature, the fabrication of TiO2 nanostructures with various morphologies. The experimental results revealed that the Ti film on the PdCl2: 30min ethanol solution with UV irradiation, 1H and 2H to 900 DEG C, get the nanowire size increased from 56.4nm to 187.95nm, the length from tens of microns to several micrometers. The catalyst keep a certain concentration, the reaction temperature is 700 degrees, 730 degrees and 800 degrees, respectively, obtained TiO2 nanosheet, nanobelts and tower structure of.XRD and Raman spectra confirmed that the Ti02 nanostructures are all rutile pure; nanowire formation for VLS growth mechanism, and nanosheets, nanobelts and tower structure is the interaction of VLS and VS.
(2) catalyst 1H at 760 DEG C, reaction 40min prepared TiO2 nano cone toothed belt. Jagged is nanobelts in the growth process, the exposed surface of the Ti+ and O- activity caused by the different growth rate of different formation. With single nanometer micro Raman imaging surface chemical group this TiO2 cone structure points distribution, surface photovoltaic testing also showed good photoelectric response, has important value for the application of TiO2 in optoelectronic devices.
(3) the photochemical deposition and impregnation deposition method respectively to synthesize Ag/TiO2 and Au/TiO2 composite structure. The metal particle deposition amount of different deposition time, deposition time is longer, the more particles adsorbed on the surface of TiO2 nanowires of Au particles. When the adsorption time is 12h, the Raman spectra showed a blue shift in the 441cm-1, this is due to excessive deposition of Au particles in the nanowire surface, squeezed into the TiO2 surface atoms, the interaction state of TiO2 surface atoms changed. The surface photovoltaic curve showed that TiO2 nanowires adsorption amount of metal particles of light absorption range has widened, response intensity, description of surface modification of metal particles to improve the photoelectric performance.

【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB383.1;O614.411

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本文編號：1400735