石墨相氮化碳的表面非共价修饰与聚集度调控研究

发布时间：2018-07-12 11:48

本文选题：石墨相氮化碳 + 光催化　；参考：《内蒙古民族大学》2015年硕士论文

【摘要】：石墨相氮化碳(g-C3N4)以其具有环境友好、组成元素含量丰富、制备简单、原料廉价和可规模化制备等优势,成为当今可见光半导体材料研究的重点,但g-C3N4的结构特点导致其光电流响应偏低,其光催化降解有机污染物和光催化分解水制氢反应的效率不高。通过自组装的方式在g-C3N4表面修饰具有反应活性的化合物或活性基团实现g-C3N4的表面功能化,是提高其光催化和化学催化活性的重要途径之一。本论文探索了g-C3N4的表面修饰及功能化新途径,对于将g-C3N4应用于降解印染废水方面具有实际意义。主要研究工作包括:铁-磷钨酸配合物(Fe-PW)依靠非共价的超分子作用力作用在g-C3N4表面对其进行功能化,修饰后g-C3N4的光催化效率和循环稳定性明显提高。在模拟太阳光条件下,Fe-PW/g-C3N4催化剂对100 mL 10 mg/L罗丹明B(RhB)的光降解效率是纯g-C3N4的1.75倍,并且经过5次循环之后,仍可以在25分钟之内,将RhB降解完全;太阳光条件下,Fe-PW/g-C3N4催化剂在15分钟内对100 mL 10mg/L甲基橙(MO)的降解率达到100%,而纯g-C3N4体系在30分钟内对相同体系MO的降解率仅为50%。经过4次循环之后,25分钟时MO的降解率为100%,在太阳光或模拟太阳光条件下,Fe-PW/g-C3N4超分子杂化催化剂对RhB和MO的降解活性都有显著提升,同时又保持了良好的循环稳定性。通过二茂铁摀离子、Fe(III)-羧酸配合物自组装在g-C3N4表面,并通过光催化反应考察其修饰效果。模拟太阳光下,二茂铁摀离子/g-C3N4超分子杂化催化剂降解MO(10 mg/L)的光催化效率是g-C3N4的1.67倍。模拟可见光下,Fe(III)-Cit/g-C3N4、Fe(III)-C2O4/g-C3N4超分子杂化催化剂对RhB(10 mg/L)的光催化效率较纯g-C3N4均提高了1.1倍。这表明,二茂铁摀离子、Fe(III)-羧酸配合物非共价修饰g-C3N4,可以实现g-C3N4的表面功能化,反应位点增加、光催化活性及循环稳定性提高。通过改变升温速率制备出了不同聚合度的g-C3N4,探索了在不同聚合度下g-C3N4光催化分解水制氢能力的变化。实验结果表明,在模拟太阳光下,TEOA为牺牲剂,负载贵金属Pt时,g-C3N4的聚合越大,其产氢能力越强。
[Abstract]:Graphite phase carbon nitride (g-C _ 3N _ 4) has become the focus of research on visible light semiconductor materials due to its advantages of environmental friendliness, abundant element content, simple preparation, cheap raw materials and large scale preparation. However, the photocurrent response of g-C _ 3N _ 4 is low due to its structural characteristics, and the efficiency of photocatalytic degradation of organic pollutants and photocatalytic decomposition of water to produce hydrogen is not high. The surface functionalization of g-C _ 3N _ 4 by self-assembly on the surface of g-C _ 3N _ 4 is one of the important ways to improve its photocatalytic and chemical catalytic activity. In this paper, a new way of surface modification and functionalization of g-C _ 3N _ 4 is explored, which is of practical significance for the application of g-C _ 3N _ 4 to the degradation of dyeing wastewater. The main research work includes: Fe-PW complexes are functionalized on the surface of g-C _ 3N _ 4 by non-covalent supramolecular forces. The photocatalytic efficiency and cyclic stability of g-C _ 3N _ 4 are improved obviously after modification. The photodegradation efficiency of 100 mL 10mg / L Rhodamine B (RhB) catalyzed by Fe-PW-g-C3N4 catalyst under simulated solar light is 1.75 times that of pure g-C3N4. After 5 cycles, RhB can be completely degraded within 25 minutes. The degradation rate of 100 mL 10mg / L methyl orange (MO) by Fe-PW-g-C3N4 catalyst in 15 minutes was 100%, while that of pure g-C3N4 system was only 50% in 30 minutes. After four cycles for 25 minutes, the degradation rate of MO was 100. The catalytic activity of Fe-PW-g-C3N4 supramolecular hybrid catalysts for RhB and MO was significantly improved under the conditions of solar or simulated sunlight, and the degradation activity of RhB and MO was improved significantly, at the same time, good cycling stability was maintained. The Fe (III) -carboxylic acid complex was self-assembled on the surface of g-C _ 3N _ 4 and its modification effect was investigated by photocatalytic reaction. Under simulated sunlight, the photocatalytic efficiency of ferrocene-mg-C3N4 supramolecular hybrid catalyst for the degradation of MO (10 mg / L) was 1.67 times higher than that of g-C3N4. The photocatalytic efficiency of Fe (III) -Citg-C _ 3N _ 4 Fe (III) C _ 2O _ 4 / g-C _ 3N _ 4 supramolecular hybrid catalyst for RhB (10 mg / L) was 1.1 times higher than that of pure g-C _ 3N _ 4. The results show that the noncovalent modification of g-C _ 3N _ 4 with ferrocene-containing Fe (III) -carboxylic acid complex can result in the surface functionalization of g-C _ 3N _ 4, the increase of reaction sites, and the improvement of photocatalytic activity and cycle stability of g-C _ 3N _ 4. G-C _ 3N _ 4 with different degree of polymerization was prepared by changing the heating rate, and the change of photocatalytic ability of g-C _ 3N _ 4 to produce hydrogen from water was explored under different degrees of polymerization. The experimental results show that the larger the polymerization of the noble metal Pt is, the stronger the hydrogen production capacity is when TEOA is used as a sacrificial agent under simulated solar light.
【学位授予单位】：内蒙古民族大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ116.2;O643.36

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