沸石材料浸润性的调控及其优异的催化性能

The wettability of zeolite catalysts plays key roles in determining the catalytic performances. Therefore, it is of great importance to design and synthesize zeolite catalysts with controllable wettabilities for excellent catalytic activities and product selectivities. The wettability of zeolites is sensitive with the concentration of Si-OH groups on the zeolite framework. Hence, we hope to artificially control the zeolite wettability by adjusting the concentration of Si-OH groups. In this project, our work will be performed on the aluminosilicate (e.g. ZSM-5, Beta) and titanosilicate zeolites (e.g. TS-1), which have been widely used in the industrial applications. Our methodology to control the wettabilities of zeolites is using organic silicon in the staring gel. After crystallization of zeolites, the organic groups could be introduced into the zeolite framework. After calcination, the methyl groups would be transformed into hydroxyl groups. As a result, the zeolite wettability could be accurately controlled by adjusting the density of hydroxyl groups in the zeolite framework. In the corresponding catalytic reactions, we expect that the zeolite catalysts with controllable wettability would exhibit more excellent catalytic performances than conventional zeolite catalysts by highly enriching the reaction substrates. The route in this work would be important for designing and synthesizing novel zeolite catalysts with high catalytic activities and excellent catalytic performances.

沸石分子筛的浸润性对于其催化活性和选择性有着重要的影响，因此研究沸石的浸润性调控对于设计合成具有高活性和高选择性的沸石催化材料具有重要意义。由于沸石的浸润性受骨架中硅羟基的影响很大，因此我们期望通过调变沸石骨架中硅羟基的浓度来有效调变沸石的浸润性。本项目选择工业上广泛应用的硅铝沸石（ZSM-5, Beta等）和钛硅沸石（TS-1）为研究对象，通过在合成凝胶中加入有机硅化合物并控制其浓度，可以获得多种有机基团修饰的沸石材料。焙烧之后，有机基团会转变成羟基，可达到将羟基进入沸石筛骨架的目的，从而有效调控其浸润性。在相应的催化反应中，期望这类浸润性可控的沸石能够高效富集反应物，有效提高反应的活性和选择性，获得比传统沸石催化材料更优异的催化性能。该方法对于设计合成具有优异性能的新型沸石催化材料具有重要意义。

沸石分子筛的浸润性的对于其催化性能有着重要的影响。因此，调控沸石材料的浸润性对于合成具有高活性和高选择性的沸石催化材料具有重要意义。在本项目中，我们采用有机硅烷作为沸石合成的部分硅源，将有机基团引入到沸石骨架中，得到疏水骨架的沸石材料；通过焙烧将有机基团转化为硅羟基，从而得到亲水的沸石骨架。基于上述合成手段，我们建立了通过吸附测试、核磁表征、接触角测试等量化表征沸石材料浸润性的方法，掌握沸石孔道浸润性影响分子扩散效率的规律。在系列催化研究中，包括ZSM-5沸石催化的水合反应、沸石封装钯纳米颗粒催化的糠醛加氢反应、沸石封装氧化锰颗粒催化的氧化腈化反应、沸石封装纳米氧化钛催化的有机污染物降解反应，通过调控沸石材料的浸润性均可以达到优异的催化性能。本项目为设计新型的沸石基催化材料提供了新的策略和理论依据。