功能化氧化硅泡沫-无限配位聚合物3D/2D杂化材料常压吸收-还原CO2的研究

The most effective and potential measure to reduce carbon dioxide emission in a large scale is carbon capture and storage/sequestration (CCS). As the principal greenhouse gas, carbon dioxide (CO2) is also a ubiquitous C1 resource, which can be converted into high value-added energy products via the reduction reaction. The combination of the CO2 capture and reduction/utilization (CCU) could be an alternative approach to address the energy penalty problem in CCS, avoid the high pressure and safety concerns, thus achieving CO2 reduction under mild conditions. However, there are some limitations such as low concentration of the captured CO2 for the next reduction step, no enough reaction driving force, poor compatibility of the components in the homogeneous system. Therefore, in this project, the functionalized silica foam (MCF) - infinite coordination polymer (ICP) 3D/2D hybrid material will be synthesized both as CO2 absorbent and as catalyst for establishing the efficient CO2 capture-reduction system. By compositing the amino modified 3D MCF and functionalized 2D ICP nanosheets, the phase-segregated structure and multi-dimensional interface can be formed as the alkaline nano reaction environment, thus improving the CO2 uptake, increasing the local concentration. The synergistic activation of CO2 and other substrate by the organic components will enhance the compatibility of different components in the reaction system. Hence, the compatible capture and catalytic reduction system can be established. In this process, the influence of microstructure and physicochemical parameters of the hybrid materials on absorption and reduction, the rules of the CO2 capture and synergistic activation effect of functional components will be investigated to explore the capture and reduction mechanism, thus benefiting the efficient reduction reaction from CO2 to formic acid and its derivatives, N-methylation products, etc. Therefore, this project would provide the theoretical foundation and scientific basis for opening up a new way of CO2 utilization and green carbon cycling under mild conditions.

CO2是地球储量最多的碳源，可通过还原反应转化为高附加值能源产品。为此，在CO2捕集和储存（CCS）中，若将捕集后的CO2直接还原转化，则无需CCS的高能耗和常规反应的CO2高压力，可实现吸收-还原的耦合反应（CCU），常压下合成能源产品，具有重要意义。然而，均相CCU过程存在吸收后CO2浓度低、还原动力不足、体系兼容性差等弊端。因此，本项目拟设计合成新型的功能化氧化硅泡沫（MCF）-无限配位聚合物（ICP）3D/2D杂化材料，建立CO2吸收-还原的非均相体系。通过将氨基修饰的3D MCF和功能化的2D ICP复合，构筑多维界面的碱性纳米反应环境，提高CO2吸收量和碳浓度，建立兼容性的吸收活化和催化还原过程。进一步研究CO2吸收规律和功能组分的协同活化效应，阐明反应作用机制，以期实现常压下从CO2到甲酸及衍生物、氮甲基化产物的高效合成，为温和条件下CO2高值化利用提供理论基础和科学依据。

CO2作为温室气体，同时也是储量丰富、无毒无害、廉价易得的可再生C1资源，为了实现可再生碳的高值化利用，开发CO2的吸收活化-催化转化耦合过程（CCU），在温和条件下将CO2转化为能源相关产品，具有重要意义。均相CCU过程存在碳浓度低、反应动力不足、体系兼容性差等弊端。本项目针对CCU，以无限配位聚合物为基础设计合成了多种分级多孔有机无机复合材料，逐级开发了一系列CCU的非均相催化体系。在化学功能和物理结构的协同调控下，通过向金属泡沫/二氧化硅泡沫/气凝胶等多孔基底中复合二维金属有机框架/无限配位聚合物材料，在纳米微环境中精确引入多功能复合组分，构筑了多维界面的纳米反应环境，从而提供多级热力学驱动力，降低了CO2活化的动力学能垒，实现了温和条件下CO2的吸收活化和原位催化转化。通过考察复合体系的物化性质和反应条件对CCU效果的影响，初步揭示了CO2活化转化的作用机制。另外，进一步尝试该类复合材料在催化转移氢化和电解水析氧反应中的应用，从CO2的资源化利用进一步拓展到清洁能源制备领域。该项目以学科交叉研究入手，对于无限配位聚合物基复合材料的合成方法、微观结构、催化功能的研究均有一定的创新性推进，为低碳减排开辟了新思路，为温和条件下可再生碳的富集和高效利用提供理论基础和科学依据。

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