Structural and interfacial engineering of well‐defined metal‐organic ensembles for electrocatalytic carbon dioxide reduction

金属-有机配位结构与界面调控电催化二氧化碳还原

Electrochemical carbon dioxide reduction(CO_(2)RR)has been generally regarded as green technologies that can convert renewable energy such as sunlight and wind into fuels and valuable chemicals.However,the large‐scale implementation of CO_(2)RR is severely hindered by the lack of high‐performance CO_(2)RR electrocatalysts.Heterogeneous molecular catalysts and metal‐organic framework with well‐defined structure and high tunability of the metal centers and ligands show great promise for CO_(2)RR in terms of both fundamental understanding and practical application.Here,structural and interfacial engineering of these well‐defined metal‐organic ensembles is summarized.This review starts from the fundamental electrochemistry of CO_(2)RR and its evaluation criteria,and then moves to the heterogeneous molecular catalysts and metal‐organic framework with emphasis on the engineering of metal centers and ligands,their interaction with supports,as well as in situ reconstruction of metal‐organic ensembles.Summary and outlook are present in the end,with the hope to inspire and provoke more genuine thinking on the design and fabrication of efficient CO_(2)RR electrocatalysts.

电催化二氧化碳还原(CO_(2)RR)利用可再生能源(如太阳能和风能)将CO_(2)转化为燃料和高附加值化学品,因而被广泛认为是“一石二鸟”的绿色技术来解决能源与环境问题.然而,CO_(2)RR的大规模应用仍严重受限于缺乏高效稳定的CO_(2)RR催化剂.非均相分子催化剂和金属-有机框架因具有明确的结构且金属中心和配体可以调节与修饰,在CO_(2)RR的基础研究和实际应用中都展现出巨大潜力.本文综述了这些具有明确结构的金属-有机配位化合物的结构与界面调控应用于CO_(2)RR领域的工作.介绍了CO_(2)RR的基础电化学、催化剂的性能评价指标(包括过电位、法拉第效率、塔菲尔斜率、转化频率和电化学能量效率)和三种常用电解池(H型电解池、流动电解池和膜电极组件)的优缺点.重点总结近期非均相分子催化剂中金属中心、配体效应和分子-载体相互作用的调控及金属-有机框架的结构工程和原位重构等方面的重点工作.迄今,具有不同金属中心(如Mn、Fe、Co、Ni、Cu和Zn等)和配体(包括酞菁、卟啉和金属中心轴向配位等)的非均相分子催化剂和金属-有机框架被报道用于高效CO_(2)RR.调节催化剂-载体相互作用,抑制催化剂团聚并增强其导电性,可有效地提高分子催化剂的活性和稳定性.制备导电金属-有机框架、在金属-有机框架中引入活性位点或促进剂并控制金属-有机框架的原位重构,为构建高效CO_(2)RR催化剂带来更多机会.金属-有机配位化合物的结构和界面工程是发展高效CO_(2)RR催化剂的重要方向.然而,金属-有机配位化合物用于CO_(2)RR仍处于初级发展阶段,充分发挥其潜力任重道远.根据目前研究面临的问题,总结和展望该领域未来应关注的方向:(1)定向合成新颖分子催化剂、金属-有机框架和载体及其结构和界面的精准调控;(2)非均相分子催化剂和金属-有机框架在CO_(2)RR的大规模应用;(3)追踪和调控非均相分子催化剂和金属-有机框架的重构;(4)阐明金属-有机配位结构和CO_(2)RR性能的构-效关系.本文为高效CO_(2)RR催化剂设计与合成提供一定参考.