Metal-organic frameworks and their derivatives for the electrochemical CO2 reduction reaction: insights from molecular engineering

Excessive fossil fuel consumption has led to a rapid increase in CO2 concentration, posing a threat to the global environment. The electrochemical conversion of CO2 back into valuable carbon-containing products offers a promising solution; however the lack of efficient electrocatalysts remains a challenge for high-efficiency CO2 reduction reaction (CO2RR). Metal-organic frameworks (MOFs) have emerged as promising electrocatalysts owing to their superior activity and well-defined active sites and are recognized as model electrocatalysts for the fundamental study of electrocatalytic reaction mechanisms. In this review, focusing on the roles of metals and the coordination environment, we have discussed the molecular engineering of MOF electrocatalysts for the CO2RR, including regulation of metal nodes, modulation of surrounding organic ligands, and post-modification of MOFs. In addition, stability of MOFs and transformation strategies through the wet chemistry method and pyrolysis treatment to obtain MOF derivatives are summarized. Metal centers and the coordination environment of N atoms and other heteroatoms of MOF derivatives are discussed for their performance in the CO2RR. Furthermore, computational simulations and advanced characterization studies are also summarized to understand the correlation between the structure and performance of MOFs and their derivatives. By overviewing the progress and current challenges of MOF electrocatalysts and their derivatives for the CO2RR, we are aiming to provide insights into design principles and propose future directions for high-efficiency electrocatalysts, paving the way toward carbon neutrality.