金屬有機(jī)框架（MOFs）材料的制備、表征及水氧化性能研究
發(fā)布時(shí)間：2018-11-13 07:14
【摘要】：MOFs是一種高孔隙率結(jié)構(gòu)多樣的結(jié)晶性材料,因其具有多孔性和熱穩(wěn)定性已成為具有發(fā)展?jié)摿Φ拇呋牧�。發(fā)展基于非貴金屬的MOF材料,并將其應(yīng)用于模擬光合系統(tǒng)II具有重要意義和應(yīng)用價(jià)值。本論文總結(jié)了水氧化催化劑的研究進(jìn)展和MOFs材料在催化領(lǐng)域的應(yīng)用,制備并表征了三種MOF-Fe、一種MOF-Eu以及兩種MOFs復(fù)合材料,研究了它們的催化水氧化性能以及對(duì)苯甲醇的催化氧化性能,最后探討了這些MOFs材料的光催化機(jī)理。其主要研究內(nèi)容及創(chuàng)新點(diǎn)如下:(1)通過靜電自組裝的方法合成了基于稀土金屬銪的MOF/GO復(fù)合材料,通過掃描電鏡(SEM)、X-射線衍射(XRD)、紅外光譜以及拉曼光譜表征了其結(jié)構(gòu),并將其應(yīng)用于不同條件下的光催化水氧化反應(yīng),研究了其催化機(jī)理。根據(jù)實(shí)驗(yàn)結(jié)果分析發(fā)現(xiàn)GO的復(fù)合有效地提高了電子遷移速率,減少了光生電子-空穴對(duì)的復(fù)合,增強(qiáng)了光催化活性。MIL-LIC-1(Eu)良好的可見光吸收性能使其成為集光敏劑與催化劑于一體的多功能多孔材料。捕獲實(shí)驗(yàn)分析發(fā)現(xiàn),光生空穴和·OH是催化過程中的活性中間體。在此基礎(chǔ)上,我們檢測了MIL-LIC-1(Eu)及其復(fù)合物在不同條件下對(duì)苯甲醇的氧化活性,并探討了對(duì)苯甲醇的氧化機(jī)理。根據(jù)實(shí)驗(yàn)結(jié)果推測,水是催化過程中的重要氧源,在有水參加的醇氧化體系中,苯甲醇的轉(zhuǎn)化率可達(dá)85.4%。此研究結(jié)果為以水為氧源的其它光驅(qū)動(dòng)氧化反應(yīng)提供了一種新思路;(2)制備了三種不同羧基配體的鐵基MOFs材料(MIL-53(Fe)、NH_2-MIL-53(Fe)和MIL-100(Fe),其對(duì)應(yīng)的有機(jī)配體分別為對(duì)苯二甲酸、2-氨基對(duì)苯二甲酸和均苯三甲酸),根據(jù)BET、循環(huán)伏安曲線、光電性能、活性中間體的捕獲結(jié)果,討論了配體對(duì)鐵基MOFs材料催化水氧化活性的影響。其中,MIL-100(Fe)的表現(xiàn)出較高的催化活性,TON值達(dá)到了119.4,TOF為0.75 min-1。結(jié)果表明,有機(jī)配體的長度和大小以及配位羧酸的數(shù)量與催化活性有直接關(guān)系。有機(jī)配體的分子體積越大、長度越長,形成的MOFs材料孔徑越大,同時(shí)也會(huì)產(chǎn)生較多的有效的活性位點(diǎn),所以就會(huì)表現(xiàn)出更好的催化活性。因此,一種含有較多配位點(diǎn)、分子長度和大小適中的有機(jī)配體的設(shè)計(jì)和篩選有助于制備出一種高活性的MOFs催化材料;(3)在NH_2-MIL-53(Fe)的基礎(chǔ)上通過后修飾的方法制備了一種新型的鐵/鈷雙金屬M(fèi)OFs復(fù)合物(FBNC),通過SEM、XRD、紅外光譜、拉曼光譜等表征其結(jié)構(gòu),檢測了FBNC在不同催化條件下的水氧化活性。通過電化學(xué)方法研究了復(fù)合物中金屬價(jià)態(tài)的變化以及光電轉(zhuǎn)換性能。研究表明,金屬鈷的引入有效地提高了前驅(qū)體NH_2-MIL-53(Fe)的水氧化和光電轉(zhuǎn)換性能。實(shí)驗(yàn)證明這種雙金屬復(fù)合物還是一種集光敏劑和電子受體于一體的多功能光催化劑,水氧化的最高TON值達(dá)到了110.5,苯甲醇氧化轉(zhuǎn)化率可達(dá)91.1%。因此,這種多功能的鐵鈷雙金屬M(fèi)OFs復(fù)合材料為光活性材料的設(shè)計(jì)和功能化修飾提供了新思路。
[Abstract]:MOFs is a kind of crystalline material with high porosity and diverse structure. Because of its porosity and thermal stability, MOFs has become a potential catalytic material. It is of great significance and value to develop MOF materials based on non-precious metals and apply them to simulate photosynthetic system II. In this paper, the research progress of water oxidation catalysts and the application of MOFs materials in the field of catalysis are summarized. Three kinds of MOF-Fe, one kind of MOF-Eu and two kinds of MOFs composites are prepared and characterized. Their catalytic water oxidation and catalytic oxidation of benzyl alcohol were studied. Finally, the photocatalytic mechanism of these MOFs materials was discussed. The main research contents and innovations are as follows: (1) MOF/GO composites based on rare earth metal europium were synthesized by electrostatic self-assembly. (SEM), X-ray diffraction (XRD),) was used for scanning electron microscopy (SEM). The structure was characterized by IR and Raman spectra, and was applied to the photocatalytic water oxidation under different conditions. The catalytic mechanism was studied. According to the analysis of the experimental results, it is found that the recombination of GO can effectively increase the electron transfer rate and reduce the recombination of photogenerated electron-hole pairs. The photocatalytic activity of MIL-LIC-1 (Eu) was enhanced, and MIL-LIC-1 (Eu) became a multifunctional porous material with Guang Min and catalyst. The trapping experiments show that photogenerated holes and OH are active intermediates in the catalytic process. On this basis, the oxidation activity of MIL-LIC-1 (Eu) and its complexes for benzyl alcohol under different conditions was determined, and the oxidation mechanism of p-benzyl alcohol was discussed. According to the experimental results, water is an important oxygen source in the catalytic process, and the conversion of benzyl alcohol can reach 85.4in the alcohol oxidation system with water. The results provide a new idea for other photo-driven oxidation reactions with water as the oxygen source. (2) three Fe-based MOFs materials with different carboxyl ligands (MIL-53 (Fe), NH_2-MIL-53 (Fe) and MIL-100 (Fe),) were prepared and their corresponding organic ligands were terephthalic acid. Based on the BET, cyclic voltammetry curves, photoelectric properties and capture results of active intermediates, the effects of ligand on the catalytic water oxidation activity of iron based MOFs materials were discussed. Among them, MIL-100 (Fe) showed high catalytic activity, and the TON value reached 119.4 min-1., which was 0.75 min-1.. The results showed that the length and size of organic ligands and the amount of coordination carboxylic acids were directly related to the catalytic activity. The larger the molecular volume and the longer the length of the organic ligands, the larger the pore size of the MOFs materials, and at the same time, the more effective active sites will be produced, so they will exhibit better catalytic activity. Therefore, the design and screening of organic ligands with more coordination sites and moderate molecular length and size are helpful to the preparation of a highly active MOFs catalytic material. (3) on the basis of NH_2-MIL-53 (Fe), a novel Fe / Co bimetallic MOFs complex (FBNC), was prepared by post-modification method. Its structure was characterized by SEM,XRD, IR and Raman spectra. The water oxidation activity of FBNC under different catalytic conditions was tested. The changes of valence state and photoelectric conversion of metal in the complex were studied by electrochemical method. The results show that the introduction of cobalt can effectively improve the water oxidation and photoelectric conversion of the precursor NH_2-MIL-53 (Fe). The experimental results show that the bimetallic complex is also a multifunctional photocatalyst with Guang Min and electron acceptor. The highest TON value of water oxidation is 110.5 and the conversion of benzyl alcohol oxidation can reach 91.1%. Therefore, this multifunctional Fe-Co bimetallic MOFs composite provides a new idea for the design and functionalization of photoactive materials.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB33;O643.36
本文編號(hào)：2328388
[Abstract]:MOFs is a kind of crystalline material with high porosity and diverse structure. Because of its porosity and thermal stability, MOFs has become a potential catalytic material. It is of great significance and value to develop MOF materials based on non-precious metals and apply them to simulate photosynthetic system II. In this paper, the research progress of water oxidation catalysts and the application of MOFs materials in the field of catalysis are summarized. Three kinds of MOF-Fe, one kind of MOF-Eu and two kinds of MOFs composites are prepared and characterized. Their catalytic water oxidation and catalytic oxidation of benzyl alcohol were studied. Finally, the photocatalytic mechanism of these MOFs materials was discussed. The main research contents and innovations are as follows: (1) MOF/GO composites based on rare earth metal europium were synthesized by electrostatic self-assembly. (SEM), X-ray diffraction (XRD),) was used for scanning electron microscopy (SEM). The structure was characterized by IR and Raman spectra, and was applied to the photocatalytic water oxidation under different conditions. The catalytic mechanism was studied. According to the analysis of the experimental results, it is found that the recombination of GO can effectively increase the electron transfer rate and reduce the recombination of photogenerated electron-hole pairs. The photocatalytic activity of MIL-LIC-1 (Eu) was enhanced, and MIL-LIC-1 (Eu) became a multifunctional porous material with Guang Min and catalyst. The trapping experiments show that photogenerated holes and OH are active intermediates in the catalytic process. On this basis, the oxidation activity of MIL-LIC-1 (Eu) and its complexes for benzyl alcohol under different conditions was determined, and the oxidation mechanism of p-benzyl alcohol was discussed. According to the experimental results, water is an important oxygen source in the catalytic process, and the conversion of benzyl alcohol can reach 85.4in the alcohol oxidation system with water. The results provide a new idea for other photo-driven oxidation reactions with water as the oxygen source. (2) three Fe-based MOFs materials with different carboxyl ligands (MIL-53 (Fe), NH_2-MIL-53 (Fe) and MIL-100 (Fe),) were prepared and their corresponding organic ligands were terephthalic acid. Based on the BET, cyclic voltammetry curves, photoelectric properties and capture results of active intermediates, the effects of ligand on the catalytic water oxidation activity of iron based MOFs materials were discussed. Among them, MIL-100 (Fe) showed high catalytic activity, and the TON value reached 119.4 min-1., which was 0.75 min-1.. The results showed that the length and size of organic ligands and the amount of coordination carboxylic acids were directly related to the catalytic activity. The larger the molecular volume and the longer the length of the organic ligands, the larger the pore size of the MOFs materials, and at the same time, the more effective active sites will be produced, so they will exhibit better catalytic activity. Therefore, the design and screening of organic ligands with more coordination sites and moderate molecular length and size are helpful to the preparation of a highly active MOFs catalytic material. (3) on the basis of NH_2-MIL-53 (Fe), a novel Fe / Co bimetallic MOFs complex (FBNC), was prepared by post-modification method. Its structure was characterized by SEM,XRD, IR and Raman spectra. The water oxidation activity of FBNC under different catalytic conditions was tested. The changes of valence state and photoelectric conversion of metal in the complex were studied by electrochemical method. The results show that the introduction of cobalt can effectively improve the water oxidation and photoelectric conversion of the precursor NH_2-MIL-53 (Fe). The experimental results show that the bimetallic complex is also a multifunctional photocatalyst with Guang Min and electron acceptor. The highest TON value of water oxidation is 110.5 and the conversion of benzyl alcohol oxidation can reach 91.1%. Therefore, this multifunctional Fe-Co bimetallic MOFs composite provides a new idea for the design and functionalization of photoactive materials.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB33;O643.36
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 王佩東;薛娟娟;胡琴漢;曲玲玲;陳秋云;;吡咯甲酮基鈷配合物:一種水氧化催化劑[J];無機(jī)化學(xué)學(xué)報(bào);2014年04期
，本文編號(hào)：2328388
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