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ZnO@CeO2和ZnO@La-CeO2核壳结构半导体材料的制备及其光催化能的研究

时间:2019-08-18 14:48来源:毕业论文
通过结合光催化还原的特点和活性,提出了关于半导体催化剂上利用其表面性质(面点/组,反应中间体)进行二氧化碳的光还原,启示了一个目前很少人研究但是却很有前途的研究信息

摘要:通过一个简单的浸渍路线,合成多种不同组分的ZnO@CeO2和ZnO@La-CeO2核壳结构半导体材料。随后对氧化锌,ZnO@CeO2和ZnO@La-CeO2核壳结构半导体材料进行了表征,分别是X射线衍射,N 2物理吸附测量,紫外可见,PL光谱,SEM,TEM和二氧化碳吸附的FTIR。表征结果证实,所得稀土改性的ZnO复合材料具有高比表面积,能减小光的吸附能力,并且不会影响晶体结构的优点。通过反应性能和CO2-FTIR发现,引入适当的氧化铈可以有效地促进CO2吸附和增强生成的b-CO32-中间体,增加Ce改性相的ZnO催化剂的甲烷产量是纯的ZnO催化剂的4.2倍。与此相反,La除了以上铈改性的ZnO催化剂更偏向于CO2和H2O混合选择性生成CH3OH。可能是由于电子迅速分离传送到催化材料表面的OH基团,这直接关系到甲醇的产量。本文通过结合光催化还原的特点和活性,提出了关于半导体催化剂上利用其表面性质(面点/组,反应中间体)进行二氧化碳的光还原,启示了一个目前很少人研究但是却很有前途的研究信息。38728
毕业论文关键词:镧铈共改性氧化锌;二氧化碳光催化;二氧化碳吸附中间体;面点
Preparation and photocatalytic properties of ZnO@CeO2 and ZnO@La-CeO2 core-shell semiconductor materials
ABSTRACT: Ce modified and La-Ce co-modified ZnO composites with rod structure and varied compositions were synthesized via a simple impregnation route. The pure ZnO, Ce modified as well as La-Ce co-modified ZnO materials subsequently were characterized in depth by combining X-ray diffraction, N2physisorption measurements, UV-vis, PL spectra, SEM, TEM and CO2 adsorbed FTIR. The characterization results confirmed that the obtained rare earth modified ZnO composites have high specific surface area, decreased light adsorption capacity, andnot affect the crystal structure. Combined to the reaction performance and CO2-FTIR, introduction ofappropriateCeO2 can effectively promoted CO2 adsorption and enhanced formation of b-CO32- intermediate, which result in the 4.2 times increase of theCH4 yields of Ce modified ZnO catalyst relative to pure ZnO catalyst. In contrast, La addition over Ce modified ZnO catalyst is contributed to selective conversion of CH3OH from the mixture of the CO2 and H2O. It is probably due to electron separated rapidly transfers to the surface OH groups, which directly related to the product of CH3OH.The combined characters and photoactivity studies reported in this paper have provided new insights to the role of surface property (surface sites/groups, reaction intermediates) in CO2 photoreduction on semiconductor catalyts, and revealed significant information that was less studied by predecessors but promising research. 源¥自%六:维;论-文'网=www.lwfree.cn
KEYWORDS: La-Ce co-modifiedZnO;CO2phototreduction;CO2 adsorbed intermediate; surface sites
目  录
1文献综述    1
1.1研究的意义    1
1.2研究现状    2
1.2.1半导体材料在光催化还原CO2中的应用    2
1.2.2 ZnO材料在催化材料中的应用    3
2实验部分    5
2.1药品试剂及实验设备    5
2.1.1试剂    5
2.1.2实验器材    5
2.2半导体材料的制备    6
2.2.1 ZnO纳米棒制备    6
2.2.2 ZnO@CeO2制备    6
2.2.3 ZnO@La-CeO2核壳结构    6
2.3半导体催化剂的表征    7
2.4 半导体催化剂光催化还原CO2性能的评价    7
2.4.1设计反应器    7
2.4.2 催化反应过程    8
3. ZnO@CeO2核壳半导体催化材料研究结果与讨论    8
3.1 X射线衍射图分析(XRD)    9
3.2 扫描电镜图分析(SEM)    10 ZnO@CeO2和ZnO@La-CeO2核壳结构半导体材料的制备及其光催化能的研究:http://www.lwfree.cn/cailiao/20190818/37771.html
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