基于杂化多孔材料构筑多相分子催化剂及光还原CO2的研究

水溶液中光催化还原CO2制备碳氢燃料是模拟光合作用、实现CO2和H2O向人工燃料转化的重要途径之一。本项目拟以苯基吡啶组装的杂化多孔材料为载体，固载金属配合物，构建水溶液中新型光催化CO2还原多相催化剂。通过探索载体骨架组成及活性中心微环境与CO2选择性吸附之间的关系，使CO2优先吸附至活性位点发生反应，发展水溶液中提高CO2光催化还原选择性的新方法；通过金属前驱体直接与骨架中的苯基吡啶配位，构筑与均相催化剂相类似的活性中心，提高多相催化剂的反应活性；利用载体骨架锚定配体以及活性位点的空间隔离效应，探究分子催化剂的失活问题，为提高其稳定性提供策略。结合CO2和水的吸附实验、固体核磁、电镜、光电子能谱等对载体的结构组成和催化活性中心进行表征，探索催化性能与催化剂结构组成之间的关联，构筑水溶液中高活性、高选择性、高稳定性的光催化还原CO2多相催化剂。

Photocatalytic reduction of CO2 into chemicals and fuels mimics natural photosynthesis in green plants using sunlight as an energy source, which is considered to have a bright prospect for future energy supply and our environment protection. In this project, we aim to construct heterogeneous molecular photocatalyst towards efficient photocatalytic CO2 conversion by using phenylpyridine-based periodic mesoporous organosilicas as the scaffold in water. Through the modification of the microenvironment of active center with hydrophobic property, the selective adsorption performance of CO2 in water will be systematically investigated. The selective preferential adsorption can help CO2 molecules react with the active species first, which can enhance the selectivity of CO2 photoreduction in water. In addition, we try to build the intact active species of homogeneous molecular catalyst structure through the direct metalation of phenylpyridine-based periodic mesoporous organosilicas. Moreover, it is expected that the encapsulation of the chelating ligand in the framework and the spatial isolation effect have the possibility to improve the stability of molecular photocatalyst, which will be comprehensively studied in the photocatalytic CO2 reduction. Through the characterization of the scaffold and the active species structure, the relationship between the catalytic activity and the composition of the heterogeneous catalyst will be concluded. With the optimization of the heterogeneous catalyst, we try to engineer an efficient and robust heterogeneous molecular catalyst with high selectivity towards photocatalytic CO2 reduction in water.