目录
I
目
录摘要................................................................................................................................I
光催化机理
1.1光催化技术 (1)
1.1.1指路器
光催化的发展.......................................................................................11.1.2
光催化的原理.......................................................................................21.2
乙酸丁酯g-C 3N 4光催化剂概述........................................................................................31.2.1
g-C 3N 4的研究进展.................................................................................41.2.2
g-C 3N 4的改性.........................................................................................51.3本论文的主要研究内容. (7)
第2章实验部分 (8)
2.1实验仪器 (8)
2.2实验试剂 (8)
2.3
2.3.1
X 射线衍射分析（XRD）......................................................................92.3.2
扫描电子显微镜分析（SEM）...........................................................102.3.3紫外-可见漫反射光谱分析（UV-Vis）...........................................10第3章
ZnO/g-C 3N 4复合材料的制备与光催化性能研究.........................................113.1 引言................................................................................................................113.2实验部分.. (11)
3.2.1
光催化剂制备.....................................................................................123.2.2
表征.....................................................................................................123.2.3光催化活性测试 (12) 3.3结果与讨论....................................................................................................123.3.1结构和形貌表征 (12) 3.3.2光催化剂的活性 (14)
3.3.3
光催化反应机理.................................................................................163.4本章小结.. (17)
哈尔滨师范大学硕士学位论文
第4章ZIF-8/g-C3N4复合材料的制备与光催化性能研究 (18)
4.1引言 (18)
4.2实验部分 (19)
4.2.1光催化剂制备 (19)
冰点渗透压
4.2.2表征 (19)
4.2.3光催化活性测试 (19)
4.3结果与讨论 (20)
4.3.1结构和形貌表征 (20)
4.3.2光催化剂的活性 (21)
4.3.2光催化反应机理 (22)
4.4本章小结 (24)
结论 (25)
参考文献 (26)
攻读硕士学位期间所发表的学术论文 (33)
哈尔滨师范大学学位论文独创性声明 (34)
哈尔滨师范大学学位论文授权使用声明 (34)
致谢 (34)
II
moto q8近年来，为了解决不断恶化的环境污染和能源短缺等问题，半导体光催化技术成为了最有希望的技术之一。在诸多光催化剂中，g-C3N4因其具备许多独特的特性及在可见光下良好的光催化活性而引起了广泛关注，然而光生载流子的快速复合对其光催化性能产生了极大的负面影响。
本论文主要介绍了g-C3N4光催化剂的研究进展及改性等内容，并且以三聚氰胺为前驱体，通过热缩聚合法合成了g-C3N4粉末，并利用复合改性法制备了两种复合材料，针对提高其光催化效率进行了两部分的研究工作。具体内容如下： （1）以乙酸锌、六次甲基四胺和尿素为前驱体，以水为溶剂，采用水热法合成了花状微米带结构的ZnO。再采用常温常压溶剂合成法，通过搅拌实现g-C3N4与ZnO的复合，通过改变g-C3N4的加入量，
制备了三种不同比例成分的ZnO/g-C3N4复合光催化剂。利用X射线衍射（XRD）和扫描电镜（SEM）表征样品的结构、成分以及微观形貌，通过光催化降解罗丹明B溶液对所得样品的光催化活性进行了表征。结果表明，当加入的ZnO与g-C3N4质量比为1:5时，合成的复合材料具有最佳的光催化活性，在可见光照射下，70分钟内对罗丹明B的降解率达到了93%，而且，ZnO/g-C3N4（1:5）复合材料经过4次循环，光催化活性没有表现出明显衰减。ZnO/g-C3N4的能带结构有利于促进光生电子-空穴的分离和快速转移，从而提升了光催化效率。
（2）以Zn(NO3)3·6H2O为锌源，2-甲基咪唑为有机配体，以甲醇为溶剂，采用常温常压溶剂合成法，实现了ZIF-8与g-C3N4两种半导体的复合。采用X射线衍射（XRD）和扫描电镜（SEM）表征样品的结构、成分以及微观形貌。结果表明ZIF-8/g-C3N4复合材料被成功制备出来，ZIF-8颗粒在g-C3N4表面上均匀生长。通过光催化降解罗丹明B溶液对所得样品的光催化活性进行了表征。实验结果表明，在可见光照射下，ZIF-8/g-C3N4复合材料50分钟内降解了97.3%的罗丹明B，比纯g-C3N4和纯ZIF-8表现出高得多的光催化活性。同时ZIF-8/g-C3N4复合材料在4次循环实验中，均保持了较高的光催化活性，显示出较好的光催化稳定性。这是由于生长在g-C3N4表面的ZIF-8小颗粒在光催化过程中可以提供更多的活性位点，并且g-C3N4和ZIF-8之间形成的界面可以有效促进光生电子-空穴的分离和转移，使光催化活性大大提高。
关键词光催化；g-C3N4；复合材料；ZnO/g-C3N4；ZIF-8/g-C3N4
Abstract
Abstract
In recent years,in order to solve the problems of deteriorating environmental pollution and energy shortage,semiconductor photocatalytic technology has become one of the most promising technologies.Among many photocatalysts,g-C3N4has attracted wide attention due to its unique characteristics and excellent photocatalytic activity under visible light.However,the rapid recombination of photocarriers has greatly negatively affected its photocatalytic performance.
This thesis mainly introduces the research progress and modification of g-C3N4 photocatalyst.Using melamine as a precursor,g-C3N4powder was synthesized by thermal condensation polymerization method,and two parts of research work were carried out to study its photocatalytic efficiency by the composite modification method. The details are as follows:
(1)Using zinc acetate,hexamethylenetetramine,and urea as precursors,and water as a solvent,a flower-like microband ZnO was synthesized by a hydrothermal method. Then a normal temperature and pressure solvent synthesis method is used to synthesize the composite of g-C3N4and ZnO by stirring.Three kinds of ZnO/g-C3N4composite photocatalysts were prepared by changing the mass of
g-C3N4.X-ray diffraction(XRD) and scanning electron microscope(SEM)were used to characterize the structure, composition and morphology of the samples.The photocatalytic activity of the obtained samples was evaluated by photocatalytic degradation of rhodamine B solution.The results show that when the mass ratio of ZnO to g-C3N4is1:5,the synthesized composite possess the best photocatalytic activity.Under visible light irradiation,the degradation of rhodamine B reached93%within70minutes.Moreover,after4cycles, the photocatalytic activity of ZnO/g-C3N4(1:5)composite did not show significant attenuation.This may be due to the band structure of ZnO/g-C3N4,which is helpful to promote the separation and rapid transfer of photo-generated electrons and holes, preventing the recombination of photocarriers,and improve the photocatalytic efficiency.
(2)With Zn(NO3)3·6H2O as the zinc source,2-methylimidazole as the organic ligand,and methanol as the solvent,the compounding of two kinds of semiconductors, ZIF-8and g-C3N4,was achieved by simple solvent synthesis at normal temperature and
哈尔滨师范大学硕士学位论文
落叶是疲倦的蝴蝶pressure with stirring.X-ray diffraction(XRD)and scanning electron microscope(SEM) were used to ch
aracterize the structure,composition and microstructure of the samples. The results show that ZIF-8particles grow uniformly on the surface of g-C3N4,and a heterojunction interface is formed between ZIF-8and g-C3N4.The photocatalytic activity of the obtained samples was evaluated by photocatalytic degradation of rhodamine B solution.The experimental results show that under visible light irradiation, the ZIF-8/g-C3N4composite material degraded97.3%of rhodamine B in50minutes, which showed much higher photocatalytic activity than pure g-C3N4and pure ZIF-8.At the same time,the ZIF-8/g-C3N4composite material maintained high photocatalytic activity after4cycles experiments,and showed good photocatalytic stability.This is because the small ZIF-8particles on the surface of g-C3N4can provide more active sites in the photocatalytic process,and the heterojunction interface formed between g-C3N4 and ZIF-8semiconductors can effectively promote the separation and transfer of photo-enerated electron-hole pairs,so its greatly enhance the photocatalytic activity.
Key words photocatalysis;g-C3N4;composite materials;ZnO/g-C3N4;ZIF-8/g-C3N4
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