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

Electrochemical carbon dioxide reduction (CO2RR) 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 CO2RR is severely hindered by the lack of high-performance CO2RR 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 CO2RR 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 CO2RR 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 CO2RR electrocatalysts.