本文選題：吸附　切入點(diǎn)：密度泛函理論　出處：《北京理工大學(xué)》2014年博士論文

【摘要】：氣候變化和生態(tài)惡化是目前全球共同關(guān)注的問題，關(guān)系到全人類的生存。在化學(xué)領(lǐng)域，與大氣環(huán)境有關(guān)的氣溶膠也引起了廣泛的關(guān)注。目前學(xué)術(shù)界認(rèn)為，氣溶膠對大氣環(huán)境的影響與其吸濕性有關(guān)，但在氣溶膠表面的許多重要的物理化學(xué)過程微觀機(jī)制的認(rèn)識上，亟需進(jìn)一步的深入研究。由于石油資源即將枯竭，人們開始關(guān)注新能源，染料敏化太陽能電池已經(jīng)成為目前科學(xué)研究的熱點(diǎn)之一。而二氧化鈦和氧化鋅是重要的光陽極半導(dǎo)體材料，對半導(dǎo)體材料體相和表面的光電性質(zhì)研究可為進(jìn)一步開發(fā)高性能太陽能電池材料提供理論依據(jù)。本文基于密度泛函理論方法，研究了水分子在氣溶膠NaNO3(001)和MgSO4(100)表面吸附機(jī)理，摻雜對鄰苯二酚吸附在銳鈦礦TiO2(101)表面電子和光學(xué)性質(zhì)的影響，以及(Zr-Al)共摻雜ZnO的電子結(jié)構(gòu)和光學(xué)性質(zhì)。主要內(nèi)容包括： (1)研究了水分子在MgSO4(100)表面的吸附機(jī)理。獲得了一個水分子和多個水分子吸附在完整的MgSO4(100)表面的穩(wěn)定吸附構(gòu)型，并揭示了水分子吸附在MgSO4(100)表面的第二和第三原子層的構(gòu)型相當(dāng)穩(wěn)定。吸附后，兩個相鄰的Mg原子之間的距離和相鄰的氧原子的距離增加，表明MgSO4(100)表面水分子的吸附有助于理解潮解過程的分子機(jī)制。此外，一個水分子更容易吸附在有缺陷的表面上。馬利肯(Mulliken)布居數(shù)分析得到水分子的Mulliken電荷從0.00變成-0.08，有缺陷的MgSO4(100)表面的Mg原子的Mulliken電荷從1.76變成1.80，表明從缺陷基底Mg原子到水分子存在少許電荷轉(zhuǎn)移。一個吸附單層(ML)定義為一個水分子對應(yīng)一個MgSO4單元。同時還計算得到了覆蓋度為0.5ML，1ML和2ML水分子吸附在MgSO4(100)表面的拉曼光譜，結(jié)果將對進(jìn)一步的相關(guān)實驗研究提供幫助。 (2)研究了單個水分子、水分子簇吸附在NaNO3(001)表面吸附機(jī)理。單個水分子傾向于吸附在表面鈉原子的橋位，水分子中的氫原子易于靠近NO3-中的氧原子，水分子中的氧原子則易于接近Na+。Mulliken布局分析表明硝酸鈉基底的鈉原子有少量電荷轉(zhuǎn)移至水分子。1ML定義為一個水分子對應(yīng)一個NaNO3單元。對覆蓋度在0.5ML，0.75ML，1ML，1.25ML，1.5ML的水分子吸附進(jìn)行了系統(tǒng)的研究。當(dāng)水分子覆蓋度為1ML的時候，吸附的水分子會通過氫鍵連接成一條水鏈。當(dāng)覆蓋度為1.5ML的時候，吸附水分子會通過氫鍵形成一個14元大環(huán)。估算的吸附在NaNO3(001)面上水分子O-H振動頻率隨著覆蓋度的降低發(fā)生藍(lán)移，與實驗上的變化規(guī)律一致。 (3)采用密度泛函理論方法研究了三種金屬元素（鋁、鎂和鉻）摻雜對鄰苯二酚吸附在銳鈦礦TiO2(101)表面體系的電子和光學(xué)性質(zhì)的影響規(guī)律。結(jié)果表明，鄰苯二酚分別吸附在完整和摻雜TiO2(101)表面結(jié)構(gòu)穩(wěn)定，且費(fèi)米能級正向移動。計算的雜質(zhì)形成能結(jié)果表明，鋁摻雜TiO2(101)表面結(jié)構(gòu)最穩(wěn)定。此外，鄰苯二酚吸附鉻摻雜TiO2(101)表面的帶隙顯著減少，同時在帶隙中出現(xiàn)一些雜質(zhì)態(tài)，結(jié)果表明，在近紅外區(qū)域，該結(jié)構(gòu)能提高光吸收能力。這一點(diǎn)可以用計算的吸收光譜來證實，鄰苯二酚吸附鉻摻雜TiO2(101)表面的光吸收最強(qiáng)，吸收光譜發(fā)生較大紅移現(xiàn)象。更重要的是，由于鉻摻雜，費(fèi)米能級正向移動，，有利于提高開路電壓。因此，計算得到的電子和光學(xué)性質(zhì)結(jié)果揭示了，對于高效的染料敏化太陽電池來說，鉻摻雜二氧化鈦是一種很有前途的光陽極材料。 (4)利用雜化密度泛函理論方法研究了(Zr-Al)共摻雜ZnO的電子結(jié)構(gòu)和光學(xué)性質(zhì)。(Zr-Al)共摻雜ZnO的形成能低，表明其結(jié)構(gòu)在能量上有利。同時與完整的ZnO相比，(Zr-Al)共摻雜ZnO光吸收譜的第一吸收峰發(fā)生紅移現(xiàn)象，這可能會提高對可見光的光催化能力。對(Zr-Al)共摻雜ZnO引入鋅和氧空位也進(jìn)行了研究。通過分析介電函數(shù)虛部的極化矢量垂直或平行于Z軸的主要吸收峰，結(jié)果表明(Zr-Al)共摻雜ZnO引入氧空位也可以提高可見光的光催化能力，引入鋅空位對(Zr-Al)共摻雜ZnO的光催化能力的增強(qiáng)影響較弱。
[Abstract]:Climate change and ecological deterioration is the current global issues of common concern, related to the survival of mankind. In the field of chemistry, and atmospheric environment related has attracted wide attention. At present, the academia thinks that its relevant hygroscopic aerosol influence on atmospheric environment, but in the understanding of the aerosol surface and many important physical chemistry the process of micro mechanism, need further study. Because of the oil resources will dry, people began to pay attention to the new energy, the dye-sensitized solar cell has become a hot topic of scientific research at present. The TiO2 photoanode semiconductor materials and Zinc Oxide is important, the research of photoelectric properties and the surface of the semiconductor material can provide theoretical basis for the further development of high-performance solar cell materials. This paper is based on the density functional theory, the study of water molecules in the gas sol NaN The surface adsorption mechanism of O3 (001) and MgSO4 (100), the influence of doping on the electronic and optical properties of catechol adsorbed on the surface of anatase TiO2 (101) and the electronic structure and optical properties of (Zr-Al) Co doped ZnO.
(1) of the water molecules in the MgSO4 (100) surface. The adsorption mechanism of the adsorption of a water molecule and a water molecule in the integrity of the MgSO4 (100) surface stable adsorption configuration, and reveals the water molecules adsorbed on MgSO4 (100) surface second and third atomic layer configuration is quite stable. After adsorption, the oxygen atom between two adjacent Mg atoms and the distance of adjacent distance increased, MgSO4 (100) showed that the molecular mechanism of the adsorption of water molecules on the surface is helpful for understanding the deliquescence process. In addition, a water molecule is easily adsorbed on the surface defects of the Mulliken population (Mulliken). Mulliken charge of water molecules from 0 to -0.08 the number of defective MgSO4 analysis, Mulliken (100) surface charge of Mg atoms from 1.76 to 1.80, that from the defect of substrate Mg atoms to the water molecule has little charge transfer. A monolayer (ML) is defined as a water It corresponds to a MgSO4 cell. At the same time, the Raman spectra of water molecules adsorbed on the MgSO4 (100) surface of 0.5ML, 1ML and 2ML are calculated. The results will provide further help for further experimental research.
(2) of individual water molecules, clusters of water molecules adsorbed on NaNO3 (001) surface. The adsorption mechanism of single water molecules tend to adsorb on the surface of sodium atom bridge, hydrogen atoms in water molecules is close to the oxygen atoms of NO3- and oxygen atoms in water molecules are easily accessible to Na+.Mulliken layout analysis showed that the sodium nitrate substrate has a small amount of sodium atom charge transfer to the water molecule.1ML is defined as a water molecule corresponding to a NaNO3 unit. The coverage in 0.5ML, 0.75ML, 1ML, 1.25ML, 1.5ML of the water molecular adsorption was studied. When the water molecule coverage is 1ML when the adsorbed water molecules will connected into a chain of water through hydrogen bonding. When the coverage is 1.5ML when the adsorbed water molecules will form a 14 yuan ring through hydrogen bonds. The estimated adsorption on NaNO3 (001) surface water molecules O-H vibration frequency with decreasing coverage of the blue shift with the experimental variable The law of chemistry is consistent.
(3) three kinds of metal elements by using density functional theory (aluminum, magnesium and chromium) doping on catechol adsorbed on the anatase TiO2 (101) effects of electronic and optical properties of the surface of the system. The results showed that the catechol adsorption respectively in intact and doped TiO2 (101) surface structure is stable, and the Fermi level is mobile. Calculation results show that the formation of impurity energy, aluminum doped TiO2 (101) surface is the most stable structure. In addition, catechol adsorption of chromium doped TiO2 (101) surface band gap was significantly reduced, there were some impurity states in the band gap. The results show that in the near infrared region, the structure can improve the light absorption ability. This can be used to calculate the absorption spectra confirmed that the catechol adsorption of chromium doped TiO2 (101) surface of the strongest absorption of light absorption spectrum has large red shift phenomenon. More importantly, the CR doping, the Fermi level is moving, there are It is helpful to improve the open circuit voltage. Therefore, the calculated results of electron and optical properties reveal that for the efficient dye-sensitized solar cells, chromium doped titanium dioxide is a promising photoanode material.
(4) was studied by using the hybrid density functional theory (Zr-Al) Co doped electronic structure and optical properties of ZnO doped ZnO (Zr-Al). The formation energy is low, the structure shows favorable in energy. At the same time compared with the complete ZnO (Zr-Al), optical absorption spectra of ZnO doped with the first absorption peak red shift, which could improve the photocatalytic ability of visible light. The (Zr-Al) Co doped ZnO into zinc and oxygen vacancies are also studied. Through the analysis of the main absorption peaks of polarization vector of the imaginary part of dielectric function in parallel or perpendicular to the Z axis, the results show that (Zr-Al) Co doped ZnO into oxygen vacancies it can improve the photocatalytic ability of visible light, the introduction of zinc vacancy (Zr-Al) on the effect of enhanced photocatalytic ability weak Co doped ZnO.

【學(xué)位授予單位】：北京理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：O647.3;TM914.4

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本文編號：1676768