超薄介孔Janus复合纳米片可控制备及乳液界面催化

Janus nanosheets have special properties due to their highly anisotropic shape besides chemistry. It is urgently needed to develop methods for preparation of functional ultrathin Janus nanosheets. Ultrathin mesoporous Janus silica nanosheets are proposed by co-assembly of surfactants and precursor silanes during sol-gel process against a solid template. Functional groups are preferentially conjugated onto the exterior surface of the silica membrane, while the other surface is protected. By disintegration of the modified membrane into small pieces and removal of the surfactant, mesoporous Janus nanosheets are achieved. Selective growth of nanoscale metallic nanoparticles onto one side (or two sides) can lead catalytic Janus composite nanosheets. Interfacial catalytic reduction of nitro compounds is selected as a model reaction in the presence of Janus composite nanosheets. The effects of composition and morphology of the Janus composite nanosheets on the reduction will be systematically investigated. This project is going to develop a simple and controllable method for preparing ultrathin functional Janus composite nanosheets, bring them efficient catalytic performance at emulsion interface, and provide a creative concept of catalysis for interfacial synthesis.

Janus纳米片因其特殊的组成和结构表现出独特的性能。简单、可控制备超薄Janus纳米片并赋予其功能性是目前亟待解决的问题。本项目在固体模板表面，通过调控硅烷偶联剂溶胶凝胶和表面活性剂共组装制备超薄介孔二氧化硅纳米膜。超声粉碎并结合选择性改性，制备超薄介孔Janus复合纳米片；通过功能基团与金属特殊作用选择负载金属纳米颗粒。以硝基化合物的氢化还原为探针反应，研究超薄介孔Janus复合纳米片在油/水乳液界面的催化性能，研究组成和形貌对乳液界面催化活性的影响。通过本项目，将发展一种简单、可控制备超薄介孔Janus复合纳米片及功能化的方法，并实现其乳液界面的高效催化，为两相界面合成的催化体系提供新思路。

Janus 材料是一类具有独特微结构和功能性的新材料，在诸多领域具有重要的应用前景。当其用作乳化剂时，能以“镶嵌”方式锚定在油/水界面，使油/水乳液更稳定。将具有催化活性的纳米颗粒与Janus结构结合构造Janus型催化剂，有望解决纳米颗粒催化剂的团聚问题，并实现催化剂重复使用。本项目开展以Janus材料为基材，利用Janus材料独特的结构和组成分区特点，选择性负载具有催化活性的纳米颗粒，探索Janus型催化剂在乳液界面的催化活性。研究包括雪人型Janus纳米颗粒、柔性聚合物Janus纳米片、二氧化硅Janus纳米片以及介孔二氧化硅/聚合物复合Janus纳米片的可控制备；通过催化剂前驱体与Janus材料的相互作用，选择性在Janus材料的一侧原位生长催化剂纳米粒子，制备Janus型催化剂；研究Janus型催化剂的乳化性能及其在乳液界面的催化活性，发展了高效、可重复利用的Janus型催化新材料。有望克服传统有机合成两相催化效率低、难分离等问题，为构筑有机合成新催化体系提供新思路。