發(fā)布時間：2018-05-15 19:05

  本文選題：催化 + 質(zhì)子傳導(dǎo)�。� 參考：《東北師范大學》2017年博士論文

【摘要】：Keggin型多金屬氧酸鹽(POMs)是經(jīng)典的多酸結(jié)構(gòu)之一,也是最穩(wěn)定、最容易合成、應(yīng)用范圍最廣及目前研究的最深入的多酸類型。本文基于Keggin型多酸的結(jié)構(gòu)特點及性能優(yōu)勢,設(shè)計合成了系列多酸基雜化材料,系統(tǒng)研究了它們的催化和質(zhì)子傳導(dǎo)性能。取得的主要創(chuàng)新性成果如下:1、制備了擔載Keggin型H_5PV_2Mo_(10)O_(40)的金屬有機框架(NENU-9),實現(xiàn)了雜化材料的納米化,在燃油深度脫硫反應(yīng)中展示了優(yōu)異性能。Keggin型H_5PV_2Mo_(10)O_(40)是為數(shù)不多的能夠以氧氣為氧化劑實現(xiàn)石油深度脫硫的催化劑之一,但問題是如何將極性的多酸引入到油相。我們采用簡單的常規(guī)溶液合成和機械研磨法,將H_5PV_2Mo_(10)O_(40)擔載到多孔MOF中得到納米化的雜化材料[Cu2(BTC)4/3(H2O)2]6[H_5PV_2Mo_(10)O_(40)](NENU-9N,BTC=均苯三甲酸)。BTC中的非極性苯環(huán)為多酸構(gòu)筑了一個疏水的外表面,并在孔中形成輸水的微環(huán)境,能夠吸附芳香族硫化物起到預(yù)濃縮作用,并限制了反應(yīng)底物與催化中心間距離,催化活性充分發(fā)揮。亞微米的NENU-9N催化劑粒子能夠均勻、穩(wěn)定地分散在模擬和真實柴油環(huán)境中,在以氧氣為氧化劑的條件下,實現(xiàn)了對芳香族硫化物二苯并噻吩(DBT)的100%催化轉(zhuǎn)化。本工作開辟了將極性多酸引入油相的新方法,實現(xiàn)了多酸催化劑在非極性溶劑中的固載、分散、分離、回收和再利用。簡便、快捷的納米晶制備方法為實現(xiàn)工業(yè)化生產(chǎn)提供了可能。2、實現(xiàn)了亞微米尺度多酸基MOF材料(NENU-3)的晶面調(diào)控,突破了傳統(tǒng)多酸基多孔MOF催化材料的孔道尺寸限制效應(yīng)。MOF作為催化劑常受其微孔特性的限制導(dǎo)致大尺寸反應(yīng)底物無法進入催化劑孔內(nèi)而催化活性大大降低。我們利用配位調(diào)節(jié)法實現(xiàn)了對多酸基MOF材料的形貌調(diào)控,通過加入與主體框架中的有機配體BTC結(jié)構(gòu)類似的對甲基苯甲酸(pTA)作為配位調(diào)節(jié)劑,NENU-3的形貌從完全暴露{111}晶面的八面體逐漸過渡到完全暴露{100}晶面的立方體。由于在{111}晶面上裸露的多酸催化活性位點比{100}晶面上更多,對于無法進入催化劑孔道內(nèi)部的大尺寸反應(yīng)底物,立方體形貌的NENU-3比八面體形貌顯示了更高的催化活性。該實驗結(jié)果打破了傳統(tǒng)多酸基多孔MOF催化材料的孔道尺寸效應(yīng),首次證實了在MOF催化劑中存在晶面效應(yīng)。應(yīng)用到生物柴油制備反應(yīng)中,發(fā)現(xiàn)立方體形貌的NENU-3催化劑對長鏈脂肪酸(C12-C22)的轉(zhuǎn)化率可達90%,是八面體形貌催化劑的4倍以上。3、在多酸基多孔MOF的三維孔道內(nèi)構(gòu)筑了連續(xù)、穩(wěn)定的氫鍵網(wǎng)絡(luò),獲得了在三正交方向具有一致質(zhì)子傳輸路徑的高性能質(zhì)子傳導(dǎo)材料。多酸是一類優(yōu)秀的固態(tài)質(zhì)子傳導(dǎo)電解質(zhì)。部分Keggin型多酸的質(zhì)子電導(dǎo)率高達0.1S·cm-1以上。但是,多酸極易溶解于水等極性溶劑,而且在受熱時(超過90℃)結(jié)晶水易失去,導(dǎo)致氫鍵網(wǎng)絡(luò)破壞、質(zhì)子傳導(dǎo)路徑被切斷而失去導(dǎo)電性能。所以,如何構(gòu)筑連續(xù)有序的氫鍵網(wǎng)絡(luò),提高固態(tài)多酸晶格中水的穩(wěn)定性,增強保水性能,是多酸用作固體質(zhì)子導(dǎo)電材料實際應(yīng)用面臨的問題。我們將給出質(zhì)子能力極強的Keggin多酸H3PW12O40(HPW)和異煙酸(Ina)作為質(zhì)子給體和氫鍵受體,引入到具有高對稱結(jié)構(gòu)的金屬有機框架(HKUST-1)中,HPW和Ina交替固載在MOF的孔道中建立了在三正交方向上一致且連續(xù)的三維質(zhì)子傳輸通路,克服了傳統(tǒng)MOF質(zhì)子導(dǎo)體中低維質(zhì)子通路導(dǎo)致的電導(dǎo)率各向異性。同時,HPW的引入,改善了雜化材料的親水性和保水性,在較低相對濕度(70%RH)下即可獲得1.81×10-3 S cm-1的質(zhì)子電導(dǎo)率,比母體框架提升了5個數(shù)量級。4、合成了具有高穩(wěn)定性的多酸-氧化石墨烯(GO)雜化塊體材料,解決了GO用作質(zhì)子傳導(dǎo)材料性能快速衰減及成膜后質(zhì)子傳輸方向與氫鍵網(wǎng)絡(luò)方向不一致的問題。以乙二胺為交聯(lián)劑、引入HPW,設(shè)計合成了具有三維多孔結(jié)構(gòu)的海綿狀HPW-GO塊體雜化材料。質(zhì)子化的乙二胺共價連接到GO表面,與多酸陰離子具有強的靜電作用,加之廣泛的氫鍵作用,使多酸穩(wěn)定的固載到有機胺修飾的GO雜化材料中。由于多酸引入到石墨烯片層間,材料的親水性能得到了明顯提高,同時由于氧化石墨烯片層上亞穩(wěn)態(tài)的環(huán)氧基團被乙二胺還原并氨基化,提供了更加穩(wěn)定的質(zhì)子傳輸位點。該材料在60%的低相對濕度下展示出了高達1.02×10-2 S cm-1的質(zhì)子電導(dǎo)率。并且連續(xù)工作一個月沒有發(fā)生明顯的性能下降。這種優(yōu)秀的性能可以歸因于三維的質(zhì)子傳輸通路、豐富的質(zhì)子跳躍位點以及塊體結(jié)構(gòu)消除了晶界電阻。5、制備了對陽離子有機染料具有高吸附性能的多酸功能化GO雜化材料,實現(xiàn)了在可見光作用下吸附材料的光再生,克服了傳統(tǒng)多酸光催化劑由于靜電作用對陽離子染料吸引而無法實現(xiàn)光降解的問題。將具有光催化活性的Keggin型多酸K4H3PTi2W10O40引入到多孔的胺功能化氧化石墨烯(FGO)中,構(gòu)筑了多酸-二元胺-氧化石墨烯的多元雜化體系。由于在POM、FGO及染料間存在疏水-疏水、π-π相互作用以及靜電吸引的協(xié)同作用,POMs-FGO雜化材料對陽離子染料亞甲基藍(MB)和羅丹明B(RhB)均展示出了優(yōu)秀的吸附能力,吸附量分別達到1095 mg/g和540 mg/g。通過線性電勢掃描確定了FGO的帶隙。由于胺化使石墨烯雜化材料價帶中的部分O2p被N2p取代,縮小了雜化材料的帶隙,實現(xiàn)了可見光吸收。同時多酸的引入對光生電子的捕捉和轉(zhuǎn)移促進了電子-空穴對的分離,實現(xiàn)了雜化材料在模擬和真實太陽光照射下對吸附染料分子的光降解,吸附性能完全再生,且多次重復(fù)使用性能無明顯降低。與傳統(tǒng)的多酸基光催化劑不同的是,由于多酸和FGO納米層對染料分子的競爭吸附效應(yīng),染料分子在多酸和FGO間形成了動態(tài)的吸附-脫附平衡,從而避免了對多酸表面的完全覆蓋。該項研究打破了傳統(tǒng)多酸光催化劑對陽離子染料光降解活性低的限制,為多酸基光催化材料的設(shè)計提供了借鑒。
[Abstract]:Keggin type polyoxometalate (POMs) is one of the classic polyacid structures. It is also the most stable, most easy to synthesize, the most widely used and the most widely studied polyacid type. Based on the structural characteristics and performance advantages of Keggin polyacid, a series of polyacid base hybrid materials are designed and synthesized. Their catalysis and protons are systematically studied. The main innovative results are as follows: 1, a metal organic frame (NENU-9) loaded with Keggin type H_5PV_2Mo_ (10) O_ (40) was prepared, and the hybrid material was nanoscaled. The excellent performance of.Keggin H_5PV_2Mo_ (10) O_ (40) was demonstrated in the deep desulfurization reaction of fuel oil, and the few were able to realize petroleum with oxygen as oxidant. One of the catalysts for deep desulphurization, but the problem is how to introduce the polar polyacid into the oil phase. We use a simple conventional solution synthesis and mechanical grinding method to carry H_5PV_2Mo_ (10) O_ (40) to the porous MOF to obtain the nanocrystalline hybrid [Cu2 (BTC) 4/3 (H2O) 2]6 [H_5PV_2Mo_ (10) O_ (40)] (NENU-9N, BTC=) three formic acid) The polar benzene ring forms a hydrophobic outer surface and forms a micro environment in which the water transport is formed in the hole. It can preconcentrate the aromatic sulfide and limit the distance between the reaction substrate and the catalytic center, and the catalytic activity is fully exerted. The sub micron NENU-9N catalyst particles can be evenly distributed in the simulation and the reality. In diesel environment, a 100% catalytic conversion of aromatic sulfide two benzo thiophene (DBT) was realized under the condition of oxygen as oxidant. This work opened up a new method of introducing polar polyacid into oil phase, and realized the immobilization, dispersion, separation, recovery and reuse of the polyacid catalyst in the nonpolar solvent. The preparation method provides the possible.2 for industrial production, realizes the crystal surface regulation of the submicron scale polyacid based MOF material (NENU-3), breaks through the pore size limitation effect of the traditional polyacid base porous MOF catalytic material,.MOF as the catalyst, which is often limited by the microporous properties of the catalyst, resulting in the failure of the large size reaction substrate to enter the catalyst hole. The morphology of the polyacid MOF material was regulated by the coordination method. By adding pTA as a coordination regulator with the structure of organic ligand BTC in the main frame, the morphology of NENU-3 was gradually transferred from eight sides of the {111} surface completely exposed to the {100} crystal surface. The cube. As the polyacid catalyzed active site exposed on the {111} surface is more than the {100} surface, the NENU-3 of the cube morphology shows higher catalytic activity than the eight surface morphology for the large size reaction substrate that can not enter the catalyst channel. The experimental results broke the traditional polyacid base porous MOF catalytic material Kong Daochi. It is first confirmed that there is a crystal surface effect in the MOF catalyst. In the preparation of the biodiesel, the conversion of the cubic NENU-3 catalyst to the long chain fatty acid (C12-C22) can reach 90%, which is more than 4 times the.3 of the eight surface catalyst, and the continuous and stable hydrogen is constructed in the three-dimensional porous MOF of the polyacid base porous MOF. Bond networks have obtained high performance proton conduction materials with uniform proton transmission paths in the three orthogonal direction. Polyacid is an excellent solid proton conduction electrolyte. The proton conductivity of partial Keggin polyacids is up to 0.1S. Cm-1. However, polyacid is easily dissolved in water and other polar solvents, and at the time of heating (over 90 degrees C) crystal water When the hydrogen bond network is destroyed easily, the proton conduction path is cut off and the conductivity is lost. Therefore, how to build a continuous and orderly hydrogen bond network to improve the stability of water in the solid polyacid lattice and enhance the water retention property is a practical problem for the use of polyacid as a solid proton conducting material. We will give a Keg with a very strong proton capacity. Gin polyacid H3PW12O40 (HPW) and isonicotinic acid (Ina), as proton donor and hydrogen bond receptor, are introduced into a highly symmetric structure of metal organic framework (HKUST-1). HPW and Ina are sequestrated in the channel of MOF to establish a consistent and continuous three dimensional proton transmission path in the three orthogonal direction, which overcomes the low dimensional proton conduction in the traditional MOF proton conductors. The conductivity is anisotropic. At the same time, the introduction of HPW improves the hydrophilicity and water retention of the hybrid material. The proton conductivity of 1.81 x 10-3 S cm-1 can be obtained under the low relative humidity (70%RH), and 5 orders of magnitude.4 are raised over the mother frame, and the high stability of the polyacid and graphene oxide (GO) hybrid block material with high stability is synthesized. GO is used as a problem for the rapid attenuation of proton conduction materials and the disagreement between the transmission direction of proton and the direction of the hydrogen bond network. Using ethylene diamine as a crosslinker, a sponge like HPW-GO block hybrid material with three-dimensional porous structure is designed and synthesized. The protonated ethamine is covalently connected to the GO surface and with the polyanic anions. With strong electrostatic action and a wide range of hydrogen bonding, polyacid is immobilized steadily into the GO hybrid material modified by organic amine. The hydrophilic property of the material has been greatly improved because of the introduction of polyacid to the graphene sheet. At the same time, the cyclic oxygen group of the metastable oxide on the graphite oxide layer is reduced and aminated by ethylenediamine. A stable proton transfer site was added. The material showed a proton conductivity up to 1.02 x 10-2 S cm-1 at 60% low relative humidity. And there was no apparent decrease in performance for a month for a month. This excellent performance can be attributed to a three dimensional proton transfer pathway, a rich proton jumping site and a block structure elimination. With the grain boundary resistance.5, a polyacid functional GO hybrid material with high adsorption properties to the cationic organic dyes was prepared. The optical regeneration of the adsorbed material under visible light was realized, and the problem that the traditional polyacid photocatalyst could not be degraded by the electrostatic action on the cationic dye was overcome. The photocatalytic activity of Keg was obtained. Gin polyacid K4H3PTi2W10O40 was introduced into the porous amine functionalized graphene oxide (FGO), and a polyacid - two - amine - graphene oxide hybrid system was constructed. There were hydrophobic, hydrophobic, pi - pi interaction and electrostatic attraction synergism between POM, FGO and dye, and POMs-FGO hybrid material to the cationic dye methylene blue (MB). Luo Danming B (RhB) showed excellent adsorption capacity, and the adsorption capacity reached 1095 mg/g and 540 mg/g. respectively to determine the band gap of FGO by linear potential scanning. Because amination made part of O2p in the valence band of the graphene hybrid material to be replaced by N2p, the band gap of the hybrid material was reduced and the visible light absorption was realized. At the same time, polyacid was introduced to photoelectricity. The separation of electron hole pairs is promoted by the capture and transfer of the subsurface, and the photodegradation of the adsorbed dye molecules in the hybrid materials under simulated and real solar irradiation is realized. The adsorption property is completely regenerated and the performance of repeated reuse has no obvious reduction. Unlike the traditional polyacid based photocatalyst, the dye is treated with polyacid and FGO nanoscale. The dynamic adsorption desorption equilibrium between polyacid and FGO is formed by the molecule's competitive adsorption effect, which avoids the complete coverage of the polyacid surface. This study breaks the limitation of the low photocatalytic degradation activity of the traditional polyacid photocatalyst and provides a reference for the design of the polyacid based photocatalytic material.

【學位授予單位】：東北師范大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：TE624.9

【參考文獻】

相關(guān)期刊論文 前1條

1 劉鎮(zhèn);吳慶銀;宋小莉;馬賽;;基于雜多酸的固體高質(zhì)子導(dǎo)體[J];化學進展;2009年05期

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本文編號：1893543