多孔碳基石墨烯-TiO2纳米复合材料的设计制备及其光催化性能研究

Photocatalytic process over semiconductor nanomaterials is an ideal technology for the treatment of environmental pollution. In the project, we intend to design and assemble new efficient photocatalytic nanomaterials, porous carbon-based graphene-TiO2 nanocomposites, which can absorb visible light as well as degradate pollutants effectively with high quantum yield. The nanocomposite architectures are fabricated functionally by porous carbon, graphene and TiO2 with well-defined geometrical shapes. Graphene is synthesized in situ in the porous carbon, which is prepared from natural plants with multi-level porous structure, and then TiO2 nanoparticles grow uniformly on the surface of graphene. The design strategy would greatly improve the poor performance of the traditional photocatalyst TiO2.The photocatalytic activities will be studied by means of photocatalytic degradation of rhodamine B and 2,4-dichlorophenol solutions, respectively. Based on the study on the degradation kinetics, the research on the oxidation/reduction reaction mechanism of the photocatalytic processes will be carried out. To interpret the synergistic mechanism between the porous carbon-based graphene with TiO2 nanocomponent, the effect of surface and interface structures of the nanocomposites on the photocatalytic process will be explored. And reasonable theory model of the photocatalytic mechanism by the nanocomposites will be investigated. So that, the project will provide both experimental reference and theoretical basis for design and preparation of new type photocatalytic materials.

以纳米半导体材料为光催化剂的光催化过程，是绿色、无二次污染的一种理想的环境污染治理技术。针对以TiO2为代表的传统光催化材料的不足，本项目拟对以TiO2为主体的纳米复合材料进行功能化设计与组装，构建一种新型高效光催化材料- - 多孔碳基石墨烯-TiO2纳米复合材料。该材料以天然植物为模板制备具有分级结构的多孔碳，以此为基体，通过设计与制备多孔碳基原位生长的石墨烯，再在石墨烯的表面均匀生长纳米TiO2颗粒，建立多孔碳-石墨烯-纳米TiO2三种材料之间的协同作用，从而大大提高材料对太阳光的利用效率和对污染物的降解能力。通过对材料的光催化活性研究，开展光催化材料表面氧化还原反应机理研究，探索材料的表面与界面结构对光催化过程的影响规律，阐明多孔碳基石墨烯载体与纳米半导体组分间的协同机制，建立合理的光催化机制理论模型，从而为新型光催化材料的设计与制备提供实验参考和理论依据。

本项目主要涉及以TiO2、石墨烯为主体，研究比表面大，光、电化学性.能优异的纳米材料。课题组设计合成了RGO-TiO2，GC-TiO2，这两种催化剂都.具有较好的光催化活性，尤其是GC-TiO2,其可见光下反应速率是工业光催化剂.P25 的三倍。首次尝试以生物多孔碳基为载体，孔内原位生长石墨烯。此外，还.研究石墨烯与碳材料在电化学上的应用以及C3N4 为载体的光催化性能研究。石.墨烯炭气凝胶比容量达到131 F/ g，经过5000 次充放电循环，电化学容量未发生.显著的下降；石墨烯复合有序介孔炭比容量高达209 F/g(电流密度为0.1 A/g)，.经过5000 次循环，其比容量未出现下降趋势。电流密度从0.1 A/g 上升至3.0 A/g.时，其比容量保留率高达92 %；mpgC3N4-CNT-1%NiS 光催化剂可见光下产氢效.率是mpg-C3N4/CNT 的147 倍；g-C3N4-CdSNRs-NiS 光解水效率达到了2563.μmol·g−1·h−1，是g-C3N4 的1557 倍。研究成果将为温室气体的利用，环境污染.的处理以及缓解能源危机提供理论和技术支持。