基于金属—有机骨架构筑复合光催化材料及其可见光光催化制氢性能

发布时间：2018-01-14 21:04

  本文关键词：基于金属—有机骨架构筑复合光催化材料及其可见光光催化制氢性能　出处：《安徽大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： 光催化材料 金属有机骨架材料 染料敏化 UiO-66 g-C_3N_4

【摘要】：能源短缺和环境污染是困扰人类社会可持续发展的两大问题,寻找和开发可再生、无污染、廉价易得的新能源是解决上述问题的重要途径。氢气具有燃烧值大、产物(H20)无污染、易储存运输等优点,是驱动人类社会发展的最有潜力的清洁能源。水是地球上最为丰富的资源,廉价易得,具有巨大的利用价值。直接利用太阳能光催化分解水制取氢气是制备清洁能源的一种重要技术。在众多的已知材料中,半导体被广泛用于光催化反应中,很多半导体光催化材料由于带隙太宽或容易光腐蚀等原因而影响了其光催化活性。因此,研究设计高效的光催化材料是光解水制氢技术发展的关键。近期,金属-有机骨架(metal-organic frameworks, MOFs)材料作为一种新型的光催化材料受到研究者的广泛关注。金属-有机骨架材料具有比表面积大、结构可设计、孔道可调控等突出优势。目前,MOFs材料的研究主要集中在其光催化环境净化方面,而关于其可见光光催化制氢的研究相对较少。本论文主要基于MOFs材料构筑复合光催化材料,并研究其可见光光催化制氢性能,具体研究内容如下：(1) CdS/UiO-66复合光催化的可见光光催化制氢性能：通过溶剂热法合成出含锆MOFs UiO-66,再利用原位合成法制备出复合光催化剂(CdS/UiO-66)。对制备的CdS/UiO-66系列催化剂进行了XRD、SEM、TEM、UV-vis、PL等形貌、结构和性质的表征。以L-抗坏血酸为牺牲剂,检测了CdS/UiO-66复合材料在可见光(λ≥420 nm)照射下的光解水制氢活性。实验结果显示,制备的CdS/UiO-66复合型光催化剂具有较高的制氢活性和稳定性,其光催化活性的提高可以归结为光生电子-空穴对在CdS/UiO-66复合物界面之间能够有效分离。当CdS/UiO-66复合材料中CdS含量为16wt.%时光催化制氢活性达到最高。(2) UiO-66/g-C3N4复合光催化的可见光光催化制氢性能：采用煅烧法,将g-C3N4纳米片层负载到UiO-66八面体上,得到UiO-66/g-C3N4光催化复合材料。在可见光(λ≥420 nm)照射下,以L-抗坏血酸为牺牲剂,检测了UiO-66/g-C3N4的光解水制氢性能。测试结果表明, g-C3N4所占比例为50%时制氢速率为单一g-C3N4制氢速率的18倍之多。UiO-66和g-C3N4的结合能够有效的提高光解水制氢活性,且催化剂稳定性较好。由于g-C3N4本身对可见光有响应,UiO-66材料的介孔结构加速光生电子的快速转移,从而能够大大提高制氢效率。(3)MIL-101(Cr)/Ni(dmgH)2非贵金属助催化剂体系的可见光光催化制氢性能：在MIL-101(Cr)的基础上,通过化学沉淀法在室温下制得非贵金属复合催化剂MIL-101(Cr)/Ni(dmgH)2。利用染料赤藓红B对MIL-101(Cr)/Ni(dmgH)2材料进行敏化,在可见光的照射下,染料的加入可使MIL-101在15%体积分数的三乙醇胺水溶液牺牲剂中光催化产氧,产氢速率可达45.9μmol·h-1。Ni(dmgH)2络合物的加入可以代替了贵金属作为助催化剂,染料的加入也扩大了材料的光响应范围。
[Abstract]:Energy shortage and environmental pollution are two major problems that haunt the sustainable development of human society. Finding and developing renewable, pollution-free, cheap and easily available new energy is an important way to solve these problems. Hydrogen has a high combustion value. It is the most potential clean energy to drive the development of human society. Water is the most abundant resource on the earth, cheap and easy to obtain. Direct use of solar photocatalytic decomposition of water to produce hydrogen is an important technology for the preparation of clean energy. Semiconductor is widely used in photocatalytic reactions among many known materials. Many semiconductor photocatalytic materials affect their photocatalytic activity due to the wide band gap or easy photocorrosion. Therefore, the research and design of efficient photocatalytic materials is the key to the development of hydrophotolysis technology. Metal-organic frameworks. As a new type of photocatalytic materials, MOFs have been widely concerned by researchers. Metal-organic skeleton materials have many advantages, such as large specific surface area, structure design, pore control and so on. The research of MOFs materials is mainly focused on the photocatalytic environment purification, but the research on visible photocatalytic hydrogen production is relatively few. This paper mainly based on MOFs materials to construct composite photocatalytic materials. The catalytic properties of hydrogen production by visible light were studied. The main contents of this study are as follows: 1) the visible photocatalytic activity of CdS/UiO-66: MOFs UiO-66 containing zirconium was synthesized by solvothermal method. The composite photocatalyst, CDs / UiO-66, was prepared by in-situ synthesis. The CdS/UiO-66 series catalysts were prepared by XRDX SEMTEM. Characterization of morphology, structure and properties of UV-Vis PL. L- ascorbic acid was used as sacrificial agent. The photocatalytic activity of CdS/UiO-66 composites irradiated by visible light (位 鈮，

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