基于地球丰产元素钴、铁和锰的多金属氧酸盐的光催化制氢性能的研究

发布时间：2018-05-30 23:20

本文选题：产氢 + 光催化　；参考：《兰州大学》2015年硕士论文

【摘要】：化石燃料是不可再生能源,并且由化石燃料燃烧所释放的二氧化碳气体所导致的全球变暖和环境污染问题也随之而来。因此,探索清洁、环境友好、可持续的非化石燃料能源已经引起了广泛的关注。由于太阳能是取之不竭、清洁、尤其是可再生的能源,因此它将成为未来新能源开发的焦点。与此同时,氢气由于具有高的燃烧值并且燃烧产物只有水(不会对环境造成污染)而被看作是化石燃料最理想替代品的候选者。因此,利用太阳能制氢将会成为一个最具有前景的策略。多金属氧酸盐是一种已经被明确定义的金属.氧簇,它是由早期过渡金属组成并且具有独特的结构特征和可调变性。多金属氧酸盐是由过渡金属.氧阴离子簇的d。电子结构所组成的因而表现出与金属氧化物半导体相类似的性质,所以它被看作是一类最具前景的制氢光催剂。此外,多金属氧酸盐还具有富氧化还原化学性质以及高的水解稳定性而被看作是多电子氧化还原过程的最佳的催化剂。因此多金属氧酸盐可作为产氢催化剂,加入光敏剂以及牺牲试剂构筑高效的均相光催化产氢体系,光敏剂的加入成功的实现了在可见光的照射下的制氢反应。多金属氧酸盐同时结合了多相催化剂稳定性的优势和均相催化剂的其他优点,许多具有制氢性能的多酸光催化剂也被研究。然而,几乎很少有基于地球丰产元素的多金属氧酸盐的光催化产氢体系被报道,因此,对于多金属氧酸盐化合物在不同光催化制氢体系中的光催化制氢性能的探索具有很大的空间。本文将以含地球丰产元素的多金属氧酸盐为对象,详细研究其在不同的光催化产氢体系中的产氢效率以及其究竟以何种机理进行产氢。主要工作包括以下几方面：(1)分别合成了含地球丰产元素钴(K7[CoⅢCoⅡ(H20)W11039].15H20),铁(Na27[Fe11(H2O)14(OH)2(W3010)2(α-SbW9O33)6]103H2O), 锰 (Na11(NH4)[(Mn11(H20))3(SbW9033)2].45H20,K18([Mn(H20)3]2Mn(H20)2][(B-β-SM9033(OH))-Mn3(H20)(B-β-SM8030(0H))]2)·16H20和Na10[Mn4(H20)2(VW9034)2].26H20)的多金属氧酸盐,并对其结构进行表征。(2)对上述所合成的化合物在不同的光催化产氢体系中,不同的反应条件下,全面考察其光催化产氢性能。同时对包括催化剂浓度,光敏剂浓度,牺牲试剂的浓度,pHs,以及助催化剂的浓度在内的一系列反应条件进行优化,而得到最佳的产氢效率。其中,含钴的多金属氧酸盐在可见光染料敏化体系中获得了目前已报道的多金属氧酸盐产氢体系中的最大的产氢速率(13395μmol h-1g-1)。含铁的多酸在紫外光光催化产氢体系中,展现了良好的稳定性,其产氢速率高达820μmol h-1g-1.(3)使用多种表征手段(例如UV-vis、红外、动态光散射、循环伏安、催化剂回收、陈化实验等)考察了催化剂在反应溶液中的水解稳定性以及在反应过程中的光催化稳定性。(4)结合稳态荧光光谱、紫外可见漫反射以及循环伏安测试,对不同光催化产氢体系的机理进行了详细的研究。
[Abstract]:Fossil fuels are non renewable sources of energy, and the global warming and environmental pollution caused by the carbon dioxide gas released by fossil fuels are also ensuing. Therefore, the exploration of clean, environmentally friendly, sustainable non fossil fuel energy has caused widespread concern. Because of the inexhaustible, clean, especially available, the solar energy is available. Renewable energy, so it will be the focus of new energy development in the future. At the same time, hydrogen will become the most promising alternative to fossil fuels because of its high burning value and combustion products only water (not polluting the environment). Therefore, the use of solar energy to make hydrogen will be the most promising strategy. Oxalate is a metal that has been clearly defined. The oxygen cluster is composed of early transition metals and has unique structural characteristics and tunable denaturalization. Polyoxometalate is made up of the D. electronic structure of the transition metal. The oxygen anion cluster is similar to the metal oxide semiconductor. In addition, polyoxometalate is also considered to be the best catalyst for the multi electron redox process, which is also considered to be the best catalyst in the multi electron redox process. Therefore, polyoxometalate can be used as a catalyst for hydrogen production, added into the photosensitizer and sacrificial reagents to build high efficiency. Phase light catalyzed hydrogen production system, the addition of photosensitizer successfully achieved hydrogen production under visible light. Polyoxometalates also combine the advantages of the stability of multiphase catalysts and other advantages of homogeneous catalysts. Many of the polyacid photocatalysts with hydrogen production properties are also studied. However, almost few are based on the earth's high yield. The photocatalytic hydrogen production system of the elemental polyoxometalate has been reported. Therefore, there is a great space for the exploration of the photocatalytic hydrogen production performance of polyoxometalate compounds in the non photocatalytic catalytic hydrogen production system. This paper will study the different photocatalytic hydrogen producing bodies in detail with the polyoxometalate containing the earth's rich elements. The main work includes the following aspects: (1) the cobalt (K7[Co III Co II (H20) W11039].15H20) is synthesized, and iron (Na27[Fe11 (H2O) 14 (OH) 2 (W3010) 2 (W3010) 6] 103H2O), and manganese (Na11) 3, respectively. Polyoxometalate of 2][(B- beta -SM9033 (OH)) -Mn3 (H20) (B- beta -SM8030 (0H))]2) 16H20 and Na10[Mn4 2. (2) the photocatalytic hydrogen production performance of the synthesized compounds in different photocatalytic hydrogen production systems is investigated and the catalytic concentration of catalyst is also included. A series of reaction conditions, such as degree, photosensitizer concentration, concentration of the sacrificial reagents, pHs, and the concentration of the promoter, were optimized and the best hydrogen production efficiency was obtained. In the visible light dye sensitization system, the maximum hydrogen production rate of the reported polyoxometalate hydrogen production system was obtained. 13395 micron mol h-1g-1). The polyacid containing iron shows good stability in the UV photocatalytic hydrogen production system, and its hydrogen production rate is up to 820 mol h-1g-1. (3) using a variety of characterization methods (such as UV-vis, infrared, dynamic light scattering, cyclic voltammetry, catalyst recovery, aging test and so on) to investigate the hydrolysis stability of the catalyst in the reaction solution. And the photocatalytic stability in the reaction process. (4) the mechanism of different photocatalytic hydrogen production systems was studied in detail with the combination of steady state fluorescence, ultraviolet visible diffuse reflection and cyclic voltammetry.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O643.36;TQ116.2

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