多酸原位调控纳米阵列材料的制备及其二氧化碳电还原性能研究

For the low activity and poor selectivity of CO2 electroreduction (CO2RR) catalysts, In this project，a new solution was explored to design and fabricate three-dimensional bimetallic sulfide nano-array electrodes based on the surface structure, then guided by the electrocatalytic function, the structure and performance of the electrodes will be optimized to achieve the goal of regulating the activity of the electrodes. Bimetallic oxide arrays with different morphologies and structures were controllably prepared in situ by the optimal selection of polyoxometalates, three-dimensional substrates and transition metal salts. The hydrophobic and hydrophobic bimetallic sulfide nanoarrays were formed by further vulcanization and post-modification, and then their properties of CO2RR were systematically studied. While exploring a new method of in-situ synthesis of composites with different surface and interface structures, the relationship between the structure, active sites and catalytic activity of the complex synthesized under different conditions was explored, so as to establish the structure-activity relationship between the electrode structure and catalytic activity. Then the catalytic mechanism will be further researched to rationally design and construct an efficient catalyst system, which will be desirable to provide theoretical and experimental foundation for the design, development and application of the CO2RR electrocatalyst system.

针对CO2电还原反应（CO2RR）催化剂存在活性低和选择性差的问题，本项目拟通过对电极表面结构进行设计制备三维双金属硫化物纳米阵列电极，以电催化功能为导向对电极结构性能优化实现电极活性调控来探索新的解决方法。择优选择多酸、三维基底和过渡金属盐引入策略，原位可控制备不同形貌结构的双金属氧化物阵列，通过硫化和后修饰形成表面亲气疏水的双金属硫化物纳米阵列，进而对复合材料的CO2RR的性能进行系统研究。探索原位合成不同表界面结构复合材料新方法的同时，寻求不同条件合成复合物的结构、活性位点以及催化活性之间的关系，建立电极结构和催化活性之间的构效关系。研究催化机理进一步理性设计和构筑高效的催化剂体系，为CO2RR催化剂体系的设计和开发应用提供一定的理论和实验依据。

传统化石能源的消耗排放大量的温室气体 CO2引发全球气候变暖、海洋酸化等相关生态问题。CO2 作为丰富的碳源，若将其转化成高附加值的含碳燃料或化学品，不仅减少大气中的含量，其转化的绿色碳资源也减轻对传统能源的依赖，对人类生存环境的改善和能源的可持续发展具有重要意义。过渡金属复合材料因不同的金属界面和交错的能带结构对反应中间体吸附能进行适当调节，提高其电子电导率进而提高其催化活性。其界面结构的多样性和潜在的电催化性能，被认为是极具应用前景的催化剂。本项目主要研究了磷钼酸和磷钨酸等多酸原位调控合成了不同形貌的纳米阵列材料，对其进行后退火得到一系列的双金属阵列纳米催化剂或者对其表面进行PTFE修饰合成亲气疏水界面的催化剂。分析了复合材料不同阵列结构与其催化性能之间的构效关系，并结合密度泛函（DFT）计算揭示了相关催化机理。通过上述研究，本项目构筑了PTFE修饰HKUST@Cu2O复合材料，复合材料对CO2吸附能力高，促进CO*和*CHO的偶联，同时促进了CO*的二聚，从而提高了催化剂对C2+产品的选择性。结合PTFE的疏水性对HER的抑制作用且催化剂表面上形成疏水表面，形成更利于CO2还原的固-液-气界面。考察了不同PTFE添加量时的接触角对复合材料性能的影响并进行优化，对碳氢产物表现出较高的法拉第效率，高达67.41%，尤其是C2H4的FE值达到46.08%。纳米阵列材料如P-CoMoO4@Ni用于析氢反应时，于电流密度100 mA/cm2时过电势仅需98 mV；N,P-CoMoO4@CF用于全解水反应时，于1.66 V时电流密度达到100 mA/cm2；复合材料FeV3O8-RB/RGO-1表现出良好的循环稳定性和优异的倍率性能。通过对阵列等复合材料电化学性能的研究、总结规律，筛选出高选择性、高活性的电极材料为更多功能性复合材料的设计和应用奠定了基础。