g-C3N4基纳米异质结的构筑及性质调控

Polymeric graphitic carbon nitride (g-C3N4) exhibits ideal conductivity and has a special layer structure. The construction of g-C3N4-based composite is different from other semiconductor materials. The controlling of interface of the composite is helpful for not only improving the separation efficiency of photogenerated holes and electrons, but also supplying useful experimental data and theoretical analysis to other similar composite materials. In this project, mercaptopropyl modified sol-gel SiO2 particles will be used as templates to create nano g-C3N4 with sheet, tube, solid fiber, and honeycomb morphologies. The formation, evolution, and controlling of the morphology will be investigated to discuss the mechanism. The mercaptopropyl group governs the morphologies of resulting samples. The other elements including B, C, N, S, and Co etc. will be doped to adjust the band gap of g-C3N4. The doping will affect the morphology and property of g-C3N4 nanomaterials. Through the growth in situ and the self-assembly via a π-π stacking interaction, the heterostructure of g-C3N4 and semiconductor will be created. Hydrophobic CdSe quantum dots with narrow band gap and semiconductor oxide such as ZnO and Co3O4 will be used for the construction of the heterostructure. The self-assembly behavior of the semiconductor materials on 1D and 2D g-C3N4 surfaces will be controlled through adjusting the ratio of water and oil phases in synthesis systems. We will further focus on the self-assembly of CdSe nanorods and the decoration of oxide nanosheets on g-C3N4 surfaces. We will aim the formation mechanism of the heterostructures and study the interface adjustment of the microstructure to find out the generation, separation, and transfer mechanism of the carriers.

石墨相氮化碳（g-C3N4）具有良好的导电性及特殊的层状结构，其复合材料构筑不同于传统半导体材料，复合材料界面的控制不仅可以解决g-C3N4材料电子空穴分离效率低的问题，而且为同类复合材料构筑提供理论依据。本项目采用巯丙基改性的SiO2凝胶颗粒作为模板制备片状、管状、针状、蜂窝状g-C3N4纳米材料，研究形貌形成、演变及控制的过程和机理，确定巯丙基控制形貌形成的机制；并掺杂B、C、N、S、Co等元素进行带隙能调控，研究形貌及性质的改变；基于原位生长及π-π堆叠效应自组装在g-C3N4材料上构筑半导体异质结构，选用窄带隙的CdSe基量子点和氧化物半导体如ZnO和Co3O4，通过油相水相比例调控研究在一维及二维g-C3N4上的自组装行为，特别是在g-C3N4表面CdSe纳米棒状异质结的自组装和氧化物片状纳米花的修饰，探索异质结构的形成机制，从界面微观结构变化揭示载流子产生、分离及转移机制。

石墨相氮化碳（g-C3N4）具有良好的导电性及特殊的层状结构，其复合材料构筑不同 于传统半导体材料，复合材料界面的控制不仅可以解决g-C3N4材料电子空穴分离效率低的 问题，而且为同类复合材料构筑提供理论依据。本项目采用巯丙基改性的SiO2凝胶颗粒作 为模板制备片状、管状、针状、蜂窝状g-C3N4纳米材料，研究形貌形成、演变及控制的过 程和机理，确定巯丙基控制形貌形成的机制；并掺杂B、C、N、S、Co等元素进行带隙能调 控，研究形貌及性质的改变；基于原位生长及π-π堆叠效应自组装在g-C3N4材料上构筑 半导体异质结构，选用窄带隙的CdSe基量子点和氧化物半导体如ZnO和Co3O4，通过油相水 相比例调控研究在一维及二维g-C3N4上的自组装行为，特别是在g-C3N4表面CdSe纳米棒状 异质结的自组装和氧化物片状纳米花的修饰，探索异质结构的形成机制，从界面微观结构 变化揭示载流子产生、分离及转移机制。四年的时间，完成了如下研究：纯的及掺杂的g-C3N4 的形貌可控合成、性质分析；量子点合成条件的调整，制备适合与g-C3N4自组装的样品，包括 形貌、尺寸及表面态的控制；纳米花状及半球花状 ZnO 及 Co3O4纳米片的制备及形貌控制，适合与 g-C3N4 自组装的样品，调整制备条件，并完成两种方式 的异质结的制备、表征及数据分析。最后获得了有应用前景的成果。