有机三嗪框架锚定的单原子铜催化剂对CO2选择性还原的电催化

The electrochemical reduction of CO2 (CO2RR) which can convert CO2 into valuable fuels or chemicals under mild conditions is one of the research hotspots in electrochemistry. Focused on the bottleneck problems such as high overpotential, low Faraday efficiency (FE), and low proportion of hydrocarbon products in CO2RR, this project proposes to anchor atomic Cu within the structure of organic triazine frameworks (CTFs) to construct Cu-CTFs electrocatalysts, taking advantage of CTFs’ adjustable structures, modulating the electronic structure and microenvironment of the catalytic Cu center through CTF structure regulation, clarifying the influential factors of the CTF structures on the activity and selectivity of the Cu sites in CO2RR and elucidating the underline mechanism. Innovatively, it is proposed by introducing position adjustable OH/CN functions into the CTFs acting as hydrogen bond donor/acceptor to stabilize the key intermediates such as*CO, *CHO through hydrogen bond interactions, thus to increase the proportion of hydrocarbon products. Combining with DFT calculation, the synergistic catalytic mechanism between the structure of CTFs and the single atom Cu in CO2RR will be developed. This research project will provide useful methodology and scientific basis for the controllable preparation of CO2RR catalysts with high activity and value product selectivity.

二氧化碳电化学还原反应（CO2RR）可在温和条件下将CO2转化为高附加值燃料或化学品，是当前研究的一个热点。针对目前CO2RR存在的过电位高、法拉第效率（FE）低以及烃类产物比例低等瓶颈，项目提出通过可控合成有机三嗪框架(CTFs)锚定Cu、制备单原子Cu催化剂（Cu-CTFs），通过调节CTFs配位点电性、构型等调控Cu电子结构和催化微环境，阐明CTFs结构对Cu-CTFs电催化活性和产物选择性的影响规律。创新性提出在CTFs结构中引入含OH/CN等末端的支链作为氢键给体/受体单元，通过优化支链长度调节其与金属Cu间距，通过与CO2还原的*CO、*CHO等关键中间体形成氢键进而稳定中间体、降低中间体形成能垒，大幅提升烃类产物的比例。结合DFT计算，探索CTFs结构和Cu对CO2选择性还原的协同催化机制。为具高活性、高附加值产物选择性的CO2RR电催化剂的研制提供科学基础。

电催化CO2还原反应（CO2RR）利用可再生电能将温室气体CO2转化为燃料或化学品，是实现碳闭环的一种潜在手段。本项目设计、制备共价有机聚合修饰的Cu催化剂，探索聚合物结构协同Cu深度还原CO2，提高CO2RR中甲烷、乙醇等高能量密度、高价值产物选择性。本项目设计、合成了多种结构新颖的功能性共价有机材料，并制备了共价三嗪框架锚定的、具有CuN2Cl2结构的单分散Cu催化剂，实现了电催化CO2RR产烃类的高选择性，最高法拉第效率达81.3%。在此基础上，本项目还研究了电解液中硫氰酸根（SCN-）对Cu电催化CO2RR选择性的影响、通过电极结构设计提高CO2转化效率的方法以及聚合物调控非Cu催化剂深度还原CO2至乙醇的方法。用原位X射线吸收谱（XAS）、原位拉曼、准原位X射线光电子能谱（XPS）及DFT计算揭示CO2RR过程中聚合物对金属活性中心电子结构、CO2RR中间体（*COOH、*CO）及析氢反应中间体形成、稳定性的影响，阐明聚合物结构与金属在提高CO2RR的活性和选择性的协同机制。