氨法热聚合制备氮化碳及其光催化性能研究

摘要本工作采用在氨气中一步热聚合的方法制备多孔石墨相氮化碳（pg-C3N4）纳米片光催化剂。本实验主要研究了合成温度对样品结构、光学性能和光催化性能的影响。分析表征结果表明，由于氨气对 NH4SCN 分解的抑制作用，七嗪环共轭杂环结构在 500 oC 左右形成，高于惰性气气氛制备 g-C3N4。在较高的温度下得到的样品中出现大面积片状形态和更清晰的孔分布。光学分析结果表明：随着聚合处理温度的升高，样品的禁带宽度逐渐增大，而荧光发射强度逐渐下降。这些结果表明，较高的反应温度优化了样品的纳米层状结构、增大了孔隙率和光生载流子的迁移率。600 oC 下制备的 pg-C3N4 纳米片在可见光照射下具有最高的光解水产氢效率。因此，这是一种全新的可合成出性能优异的半导体纳米片光催化剂的方法。83159

毕业论文关键词：氮化碳；纳米片；半导体；氨气；光催化；产氢

Abstract Porous graphitic carbon nitride (pg-C3N4) nanosheets have been prepared via one-step ammonia thermopolymerization method。 The effects of synthetic temperature on the structural, optical and photocatalytic properties of the samples were investigated。 Characterization results show that the well heptazine-based conjugate heterocyclic structure formed over 500 oC, attributed to the inhibitory effect of ammonia to the decomposition of NH4SCN。 Precise nanosheet morphology and more pore distribution with enlarged surface area appear for the samples obtained under higher temperature。 Optical analysis results evidence that the bandgap of samples become widening and PL intensity quench gradually as the treating temperature increases。 The results demonstrate that higher polymerization temperature improves the nanolayer structure, porosity and migration rate of photo-induced carriers of samples。 The pg-C3N4 nanosheets prepared at 600 oC presents highest photocatalytic activity for hydrogen evolution from water under visible-light irradiation。 This study demonstrates a novel strategy for synthesis and optimization of polymer semiconductor nanosheets with gratifying photocatalytic performance。

Keywords: Carbon nitride nanosheets; Semiconductors; Ammonia; Photocatalysis; H2 evolution

第一章绪论 1

1。1 概述 1

1。1。1 能源 1

1。1。2 氢能 1

1。1。3 光催化分解水制氢 1

1。2 光催化技术 2

1。2。1 研究背景 2

1。2。2 光催化简介 2

1。2。3 半导体光催化原理 3

1。2。4 光催化剂存在的问题 4

1。2。5 影响半导体光催化反应的因素 4

1。3 氮化碳光解水产氢 5

1。3。1 研究背景 5

1。3。2 氮化碳简介 5

1。4 氮化碳在国内外存在的问题及对策 7

1。4。1 形貌调控 7

1。4。2 掺杂改性 8

1。4。3 贵金属沉积氨法热聚合制备氮化碳及其光催化性能研究:http://www.youerw.com/huaxue/lunwen_97868.html