磷酸银基光催化分解水复合材料的设计合成和性能研究

发布时间：2018-06-02 12:33

本文选题：磷酸银 + 石墨相氮化碳　；参考：《江苏大学》2017年硕士论文

【摘要】：近年来,能源紧缺和环境污染形势越来越严重,也是人类所面临的重大挑战。如何有效解决这两大问题已成为全社会关注的焦点,也是当前科学研究领域亟需解决的关键问题。太阳能是一种清洁、可持续利用和无污染的能源,具有一定能带位置的半导体材料能够有效利用太阳能光催化分解水产生氢气和氧气,将光能转换为化学能,因此基于半导体材料的太阳能光催化技术被认为是解决环境污染和能源紧缺最有效的方法之一。设计合成新型高效的复合材料应用于太阳能光催化分解水研究成为当前研究的热点和难点问题。本论文主要通过将半导体材料(如C_3N_4、MoS_2)和磷酸银半导体材料有效复合,制备出具有固定组成和微观形貌的复合材料并应用于太阳能光催化分解水研究:(1)充分结合前驱体共聚改性、高温烧结、静电驱动自组装及原位反应等手段方法,将带正电荷的银离子吸附在在非金属元素改性氮化碳纳米结构材料上,后通过添加的磷酸盐与吸附在氮化碳基体上银离子的原位反应,实现改性氮化碳/磷酸银复合材料的可控制备。复合材料的组成、结构、形貌等测试分析结果表明其具有相对固定的化学组成、晶体及化学结构、可控的形貌及界面。光催化评价结果显示:复合材料的太阳能光催化分解水产氧活性相对于纯的磷酸银材料来说提升较多。(2)基于超声剥离技术获得少层结构的片状二硫化钼材料,将其与磷酸银材料有效组装,获得片状二硫化钼/磷酸银复合材料;利用水热合成技术、静电驱动自组装及原位反应等手段,制备出花状二硫化钼/磷酸银复合材料。扫描电镜及透射电镜等分析结果显示:两体系复合材料均具有较好的微观形貌和界面复合;化学组成、晶体结构以及光谱测试结果表明:复合材料的化学组成相对固定,微观形貌及界面可控;对可见光的吸收和利用效果好。光解水测试结果表明:复合材料在模拟太阳光下光催化分解水产氧效率要远远高于纯磷酸银;所获得的花状二硫化钼/磷酸银复合材料相对于片状二硫化钼/磷酸银复合材料而言,可见光催化分解水产氧效率要更高。(3)进一步采用电子自旋共振(ESR)的原位检测技术,实时监测不同材料在可见光驱动下光催化分解水实验过程中产生的活性含氧自由基种类及浓度,通过不同含氧自由基种类和浓度的分析,确定不同复合材料光催化分解水过程中起主导作用的活性基团,并结合其他分析测试结果合理推测各系列复合材料的光催化反应机理。
[Abstract]:In recent years, energy shortage and environmental pollution are becoming more and more serious. How to solve these two problems effectively has become the focus of attention of the whole society, and is also the key problem that needs to be solved in the field of scientific research. Solar energy is a clean, sustainable and pollution-free energy source. Semiconductor materials with certain energy positions can effectively use solar energy to catalyze the decomposition of water to produce hydrogen and oxygen, and convert light energy into chemical energy. Therefore, solar photocatalysis based on semiconductor materials is considered to be one of the most effective methods to solve environmental pollution and energy shortage. It has become a hot and difficult problem to design and synthesize new and efficient composite materials for solar photocatalytic decomposition of water. In this thesis, the composite with fixed composition and micro-morphology was prepared by effectively compounding semiconductor materials (such as C _ S _ 3N _ 4MoS _ 2) with silver phosphate semiconductors and applied to the study of photocatalytic decomposition of water by solar energy. By means of high temperature sintering, electrostatic self-assembly and in-situ reaction, silver ions with positive charge were adsorbed on non-metallic elements modified carbon nitride nanostructures. The controllable preparation of the modified carbon nitride / silver phosphate composite was realized by the in-situ reaction of the added phosphate and the silver ion adsorbed on the carbon nitride matrix. The composition, structure and morphology of the composite show that the composite has relatively fixed chemical composition, crystal and chemical structure, controllable morphology and interface. The results of photocatalytic evaluation showed that the photocatalytic activity of the composite was much higher than that of pure silver phosphate) the lamellar molybdenum disulfide material with less layer structure was obtained based on ultrasonic stripping technology. The flake molybdenum disulfide / silver phosphate composite was prepared by hydrothermal synthesis, electrostatic self-assembly and in-situ reaction. The results of scanning electron microscopy and transmission electron microscopy show that the composites have good microstructure and interfacial compounding, and the chemical composition, crystal structure and spectrum of the composites are relatively fixed. The microstructure and interface are controllable, and the absorption and utilization of visible light are good. The results of photolysis water test showed that the efficiency of photocatalytic decomposition of aquatic oxygen was much higher than that of pure silver phosphate under simulated sunlight. Compared with the flake molybdenum disulfide / silver phosphate composite, the visible photocatalytic decomposition efficiency of aquatic oxygen is higher than that of the flake molybdenum disulfide / silver phosphate composite. The kinds and concentrations of active oxygen free radicals produced by different materials in the process of photocatalytic decomposition of water under visible light were monitored in real time, and the types and concentrations of different oxygen free radicals were analyzed. The active groups which play a leading role in the process of photocatalytic decomposition of water in different composite materials were determined, and the photocatalytic reaction mechanism of each series of composite materials was reasonably inferred in combination with other analytical results.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33;O643.36

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