基于沸石咪唑酯骨架/锗酸锌复合结构的CO2富集型光催化剂制备及其性能研究

Photocatalytic reduction of CO2 to valuable hydrocarbons using solar energy at room temperature and ambient pressure is one of the best solutions to both the global warming and the energy shortage problems. The small surface area and low CO2 adsorption capacity of traditional inorganic semiconductor photocatalysts greatly restricted their further improvement in photocatalytic activity. How to achieve CO2 enrichment on the surface of the photocatalyst has become one of the key technologies of this research field. In this project, we try to employ Zn2GeO4 as a typical inorganic semiconductor photocatalyst, Zeolitic Imidazolate Frameworks (ZIFs) with desirable CO2 adsorption property will be synthesized and attached onto Zn2GeO4 to produce a novel kind of composite photocatalysts. The adsorption capacity of CO2 of the photocatalyst will be greatly enhanced, resulting in a substantial improvement in photocatalytic conversion of CO2 to fuels in aqueous medium.This study will involve the following tasks:1) Study the CO2 adsorption characteristics of functionalized ZIFs in aqueous medium and demonstrate the relactionship between the surface structure of ZIFs and the CO2 adsorption capacity; 2) Optimize the preparation process of the composite material and reveal the growth mechanism of ZIFs particles on Zn2GeO4 nanomaterials;3)Establish the structure-functionality relationship between the ZIFs/Zn2GeO4 physicochemical characteristics and photocatalytic activity, and explore the reaction mechanisms of the photoreduction process with prepared composite photocatalysts. The project is proposing novel experimental and theoretical basis for the study and practical application of photocatalytic reduction CO2. The execution of this objectives will also advance a new route for exploring new photocatalysts.

利用光催化还原将CO2转换成碳氢燃料是解决能源危机和环境污染最有前途的方法之一。传统的无机半导体光催化剂比表面积小CO2吸附性能差，极大地制约了其光催化还原CO2活性的提高。本项目拟采用锗酸锌（Zn2GeO4）作为典型无机半导体光催化剂，将其与官能化沸石咪唑酯骨架材料（ZIFs）复合，构建新型ZIFs/Zn2GeO4复合光催化剂，借助ZIFs组元提高催化剂的CO2吸附量，以实现催化剂表面CO2的富集和高效还原。主要研究内容为:1)研究ZIFs材料在水溶液中的CO2吸附特性，明确ZIFs表面结构与吸附性能之间的关系；2)优化复合材料制备工艺，揭示ZIFs颗粒在Zn2GeO4纳米材料表面的生长机理；3)阐明复合材料结构和表面特性与光催化性能之间的构效关系，探讨其光催化还原CO2的反应机理。本项目的实施将为光催化还原CO2的实际应用提供实验基础和理论依据，并为新型光催化剂的开发提供一条新的路径。

CO2吸附性能差是制约半导体光催化还原CO2活性的关键因素之一。本课题将半导体材料与ZIFs复合大幅度提高了催化剂的CO2吸附量。系统研究了ZIFs的CO2吸附性能，发展了ZIF-8基复合材料的制备方法，深入研究了其生长机理及光催化还原CO2性能；通过微结构调控制备了一系列高催化活性光催化剂，为开发高效光催化材料提供了坚实基础。主要研究内容和成果如下：（1）制备了ZIF-8/Zn2GeO4纳米棒，阐述了其生长机理，ZIF-8的存在提高了催化剂表面CO2的吸附量，从而提高了其光催化还原CO2活性；（2）设计合成了TiO2/ZIF-8光催化剂，引入ZIF-8后提高了Cr(VI)在催化剂表面的吸附性能，促进了光生载流子的分离，从而提高了其光催化活性；（3）以ZIF-L薄膜作为模板和反应物，首次制备了多孔ZnO纳米片光阳极，其独特的多孔结构提高了DSSC太阳能电池效率；（4）首次制备了99% {110}面暴露的ZnGa2O4微米花，阐述了其生长机理，结果证明其具有很好的光催化还原CO2活性；（5）发展了一种锗酸盐一维材料的大面积制备方法，成功制备了Cd2Ge2O6, Zn2GeO4和PbGeO3一维纳米结构，阐述了其形成机理；（6）制备了单分散的In2O3和Pr2Sn2O7介孔小球，其结构有利于提高材料的光催化/气敏性能；（7）以Zn2GeO4为前驱物和模板，发展了大比表面积可见光响应的(Zn1+xGe)(N2Ox)固溶体光催化剂的可控制备，研究了其光催化还原CO2活性。项目执行期间在ACS Appl. Mater. Interfaces, J. Mater. Chem. A, Inorg. Chem., Chem. Eur. J., Microporous Mesoporous Mate.等期刊共发表文章13篇，申请中国发明专利2项，培养硕士生5名。