石墨烯的制备及其在光驱动产蒸汽中的应用研究

发布时间：2018-06-18 06:34

本文选题：石墨烯 + 太阳能　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：能源危机是目前人类无法回避且关系到人类命运的世界性问题,化石能源终将耗尽枯竭,寻找、开发、利用新的可再生能源是各国研究学者共同努力的目标。太阳能作为一种新型的可再生能源,具有很多个突出的优点,如果太阳能的研究得到突破,很可能在未来成为能源主要的供给方式,实现人类社会的可持续发展。目前太阳能主要的利用方式有太阳能光电转换和太阳能光热转换两种。在光热转换中工质的吸收能力直接决定了太阳能的转换效率。一种高吸收率的工质对于提高直接式太阳能集热器的效率来说至关重要。石墨烯作为一种新型二维纳米材料具有优异的光学、热学、力学、电学等特性,其在太阳能光热转换、光驱动蒸发、光催化等领域具有广阔的应用前景。本课题在国内外有关石墨烯的制备、光热转换特性及太阳能光驱动蒸发的基础上,以石墨烯纳米流体和石墨烯复合膜为主要研究对象,采用实验研究的方法在直接吸收式太阳能集热器上进行光热蒸发实验,得到光热蒸发特性及变化规律。采用抗坏血酸还原氧化石墨烯的方法制备石墨烯,并进行相关表征,根据表征结果优化石墨烯制备方法,获得可用于光热产蒸汽实验的高质量石墨烯纳米颗粒。利用制备的石墨烯纳米颗粒配制出不同质量浓度的石墨烯纳米流体,并通过紫外-可见分光光度计监测纳米流体质量浓度随时间的变化,表征其稳定性。结果表明,采用抗坏血酸还原氧化石墨烯的方法可制备稳定性良好的石墨烯纳米颗粒。搭建光热蒸发实验台进行光热蒸发实验,建立相应的计算模型,利用实验测量温度和质量变化等参数得到石墨烯纳米流体的温升规律和蒸发规律,计算出光热蒸发效率。改变实验条件,研究不同浓度的石墨烯纳米流体的光热蒸发规律和不同光强对石墨烯纳米流体光热蒸发的影响。结果表明,纳米流体的浓度较低时其集热效率高于蒸发效率,当纳米流体浓度增大时,其蒸发、产蒸汽效率较高。采用抽滤的方法制备石墨烯复合膜,将石墨烯复合膜在光热蒸发实验台上进行光热蒸发实验,得到石墨烯复合膜的温升规律和蒸发规律,并计算出光热蒸发效率;研究不同石墨烯用量和不同光强对石墨烯复合膜的光热蒸发的影响。同时与石墨烯纳米流体的光热蒸发实验进行对比,分析两者之间的差异。结果表明,复合膜在石墨烯含量较低时就有不错的吸收能力,其集热效率高于蒸发效率,当石墨烯含量增大时,其蒸发、产蒸汽效率均较高。相对于石墨烯纳米流体,在直接吸收太阳能产蒸汽过程中,石墨烯复合膜产蒸汽性能更优。
[Abstract]:The energy crisis is a worldwide problem that human beings can not avoid and relate to the fate of mankind. Fossil energy will eventually be exhausted, find, develop and utilize new renewable energy, which is the goal of the joint efforts of researchers from all over the world. Solar energy, as a new type of renewable energy, has many outstanding advantages. If the research of solar energy breaks through, it will probably become the main way of energy supply in the future and realize the sustainable development of human society. At present, there are two main ways of solar energy utilization: solar photovoltaic conversion and solar photothermal conversion. In photothermal conversion, the absorptive capacity of working fluid directly determines the conversion efficiency of solar energy. A high absorptivity working medium is essential to improve the efficiency of direct solar collectors. Graphene, as a new two-dimensional nano-material, has excellent optical, thermal, mechanical and electrical properties. It has a broad application prospect in solar photothermal conversion, photo-driven evaporation, photocatalysis and so on. On the basis of the preparation of graphene, photothermal conversion characteristics and solar photo-driven evaporation at home and abroad, the main research object of this project is graphene nano-fluid and graphene composite film. The photothermal evaporation experiment was carried out on the direct absorption solar collector by using the method of experimental study, and the characteristics and variation of photothermal evaporation were obtained. Graphene was prepared by ascorbic acid reductive oxidation of graphene and characterized. According to the results, the preparation method of graphene was optimized to obtain high quality graphene nanoparticles which can be used in the experiment of photothermal steam production. Graphene nano-fluids with different mass concentrations were prepared by using the prepared graphene nanoparticles, and their stability was characterized by UV-Vis spectrophotometer. The results showed that graphene nanoparticles with good stability could be prepared by ascorbic acid reduction method. The photothermal evaporation experiment bench was built and the corresponding calculation model was established. The temperature rise law and evaporation law of graphene nano-fluid were obtained by measuring the temperature and mass change of the experiment, and the photothermal evaporation efficiency was calculated. The photothermal evaporation of graphene nanofluids with different concentrations and the effects of different light intensities on photothermal evaporation of graphene nanofluids were studied by changing the experimental conditions. The results show that the heat collection efficiency of nano-fluid is higher than that of evaporation when the concentration of nano-fluid is low, and when the concentration of nano-fluid increases, the efficiency of steam production is higher when the concentration of nano-fluid is increased. The graphene composite membrane was prepared by filtration method. The photothermal evaporation of graphene composite membrane was carried out on the photothermal evaporation test bench. The temperature rise and evaporation law of the graphene composite membrane were obtained, and the photothermal evaporation efficiency was calculated. The effects of different amount of graphene and different light intensity on photothermal evaporation of graphene composite film were studied. At the same time, compared with the photothermal evaporation experiment of graphene nano-fluid, the difference between them was analyzed. The results show that the composite membrane has a good absorption capacity when the content of graphene is low, and its heat collection efficiency is higher than that of evaporation. When the content of graphene increases, the evaporation and steam production efficiency are higher. Compared with graphene nano-fluid, graphene composite film has better steam production performance in the process of direct absorption of solar energy to produce steam.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;TK519

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