基于钛基多孔光催化材料光还原CO2的研究

With the intensification of the global greenhouse effect, CO2 photo-reduction become a hot research in the field of environment and energy. However, the troditional photocatalysts used for the reduction of CO2 are still having a very low efficiency. This project intends to develop a series of titanium-based porous photocatalyst with superior photocatalytic performance for CO2 reduction. The doping modification is carried out on the TiO2 nanoparticles loaded on SiO2 mesoporous materials to improve the visible light photo-reduction activity. And the chemical modification of some organic dyes on the composite surface is in order to enhance its visible light absorption. The further super-hydrophobic modification on composite surface could enhance the CO2 molecules absorption on the catalyst surface, there by, improving the reaction rate of CO2 photo-reduction. After the above mentioned modifications,the titanium-based composite has a high visible light utilization and CO2 reduction efficiency.On the other hand, different aromatic polycarboxylic acid is used as the organic linkers to prepare the titanium-based MOFs porous materials. The light absorption of Ti-MOFs could be transfer from UV light to the visible light region, by adjusting the charge transfer between metal ions and organic ligands. The composition, pore structures and pore size distribution can be facilely tuned by the modifications on the metal ions and the organic ligands, which results into a strong selective adsorption of CO2 molecules on MOFs surface. This project also intends to study the structure-activity relationship between the titanium-based porous materials and the CO2 reduction, in order to reveal the nature of the CO2 photo-reduction mechanism. These results will provid the experimental and theoretical basis on the future practical application of this titanium-based porous material to the field of CO2 photo-reduction.

随着全球温室效应的加剧，CO2光催化还原成为环境和能源领域的研究热点。然而，目前可供选择的光催化剂还原CO2的效率还很低。本项目拟开发一系列具有高光还原CO2性能的钛基多孔光催化材料。对负载TiO2的SiO2介孔材料进行掺杂改性，及表面有机物化学修饰，以提高其可见光区的还原活性。对其进行进一步的表面超疏水改性，以提高CO2分子在催化剂表面的吸附，从而提高其光还原反应速率。另一方面，以不同芳香类有机多酸为连接配体，制备钛基MOFs多孔材料。通过调节有机配体与金属中心之间的电荷跃迁，实现MOFs在紫外及可见光区的响应。通过改变有机配体的种类，调节MOFs的孔道结构及孔径分布，实现CO2分子在MOFs表面的选择性吸附。通过各种表征手段，研究钛基多孔光催化材料与CO2光还原之间的构效关系，揭示影响CO2光还原反应的本质因素，为钛基多孔光催化材料在CO2光还原领域的实际应用提供实验基础与理论依据。

随着全球温室效应的加剧，CO2光催化还原成为环境和能源领域的研究热点。然而，目前可供选择的光催化剂还原CO2的效率还很低。本项目已开发一系列具有高光还原CO2性能的钛基多孔光催化材料。我们研制了经济的NH4F诱导疏水改性策略来增强介孔TiO2-SiO2表面的CO2的吸附量，在疏水修饰后，TiO2-SiO2光还原CO2选择性生成甲烷的活性大大提高。通过水热法制备得到具有{001}暴露面的TiO2–x光催化剂, 该催化剂具有较好的可见及近红外吸收，较高的电子空穴分离效率，以及特殊晶面的暴露，所制备催化剂在光催化还原CO2选择性制备甲烷的测试中表现出很高的活性。双助催化剂空间分离的结构是通过分别在多级孔道TiO2-SiO2的骨架内外生长Pt和CoOx得到，提高了CO2光催化还原活性及CH4生成的选择性。结合Pt纳米颗粒的不同粒子尺寸变化的几何特征和电子性质的多样性文本分析，发现了Pt纳米粒子在CO2PR反应中对活性和选择性具有突出的尺寸效应。通过各种表征手段，研究钛基多孔光催化材料与CO2光还原之间的构效关系，揭示影响CO2光还原反应的本质因素，为钛基多孔光催化材料在CO2光还原领域的实际应用提供实验基础与理论依据。