缺陷诱导介孔超薄二维组装体的精准控制合成与性能研究

The purpose of this project is to design and synthesize mesoporous ultrathin two-dimensional semiconductor materials, and control the surface defects, which induces the assembly at certain sites for heterogeneous constituents and realizes the exactly controllable synthesis of mesoporous ultrathin two-dimensional assemblies. The laminated lyotropic liquid crystal mesophase of specific structure is formed via evaporation-induced self-assembly approach, realizing the dual preferred orientation for mesoporous channel and crystallographic plane through controlling the channel and crystal orientation. The mesoporous ultrathin two-dimensional semiconductor TiO2 and g-C3N4 catalysts with controllable surface defects can be obtained through controlling the reducing conditions. The functional heterogeneous constituents (single-atoms, clusters, quantum dots, etc.) are assembled at certain sites through defects-induced assistant technique which leads to charge unbalance, and fabricating multi-functional mesoporous ultrathin two-dimensional heterojunction assemblies. In order to promote the practical application process of mesoporous ultrathin two-dimensional assemblies in photocatalytic and photoelectrocatalytic fields, the microstructure change of materials during catalytic process, the effect of catalytic performance for catalytic active center and electronic structure change, the essence of interaction between heterogeneous constituents, the relationship between the structure and property, the surface energy level of the composites, the reaction dynamics process and the mechanism of energy transfer, the information of transfer and separation for photogenerated charge carriers will also be performed, utilizing the theoretical calculation, wavelet transform combined with time-resolution synchrotron radiation quick X-ray absorption fine structure (QXAFS) technique.

本项目拟设计合成介孔超薄二维半导体材料，对其表面缺陷进行调控，缺陷诱导异质组分在特定位置进行组装，实现高性能介孔超薄二维组装体的精准控制合成。采用蒸发诱导自组装方法形成特定结构的层状溶致液晶介相，调控其孔道和晶粒取向实现对孔道及晶面的双重择优取向，控制还原条件得到表面缺陷可控的介孔超薄二维TiO2和g-C3N4。利用缺陷导致的电荷失衡诱导功能性异质组分（单原子、簇、量子点等）组装在特定位置，构筑多功能介孔超薄二维异质结组装体。理论计算、小波变换分析结合时间分辨同步辐射原位测试技术探测催化反应中材料的微观结构变化，确定光（电）催化反应活性中心及电子结构变化对催化性能的影响，揭示异质组分间相互作用的本质及材料结构与性能之间的关系、组装体表面态能级及光生载流子的动力学过程和能量传递机制，提供载流子迁移、分离等表面态信息，进而明确催化反应机制，推动介孔超薄二维组装体在光（电）催化领域的实用化进程。

缺陷工程和二维超薄结构是提高电荷分离效率和光催化性能的有效策略。本项目设计合成了介孔超薄二维半导体材料，对其表面缺陷进行了调控，缺陷诱导异质组分在特定位置进行组装，实现了高性能介孔超薄二维组装体的精准控制合成。采用蒸发诱导自组装、溶剂热方法形成特定结构的溶致液晶介相，控制高温氢化还原条件得到了表面缺陷可控的介孔超薄二维半导体TiO2和g-C3N4纳米片，光催化产氢性能较原始样品提高了6-10倍。将其作为宿主，采用低温湿浸渍等方法将导功能性异质组分组装在特定位置，构筑了系列多功能介孔超薄二维异质结组装体，显著提高了电荷分离效率和可见光催化性能。理论计算结合时间分辨测试技术探测了催化反应中材料的微观结构变化，确定了光催化反应活性中心及电子结构变化对催化性能的影响，揭示了异质组分间相互作用的本质及材料结构与性能之间的关系及光生载流子的动力学过程和能量传递机制，进而明确了光催化反应机制，推动了介孔超薄二维组装体在光催化领域的实用化进程。此外，为了进一步提高电荷分离效率和太阳光利用率，采用界面工程策略制备了系列高性能异质结太阳光催化材料，包括串联异质结、Z型异质结、S型异质结等，显著提高了可见-近红外光的吸收，实现了光生电荷的高效定向转移和分离，进一步提高了太阳光驱动的光催化性能，拓展了超薄介孔光催化材料在能源与环境领域的应用。