Strategies to Optimize Metal-Organic Frameworks for Efficient Electrocatalytic CO2 Reduction

Electrocatalytic CO2 reduction reaction (ECRR) for fuel products provides a promising approach to reducing the carbon footprint and storing renewable electricity in the chemical bonds. Metal-organic frameworks (MOFs) are promising catalysts for ECRR due to their porous, well-defined, and adjustable architectures, which are beneficial for the enrichment of CO2, and exploration of the structure-activity relationship and catalytic mechanisms. This review provides a comprehensive overview of the design strategies employed in MOF-based catalysts for enhanced ECRR performance, including activity optimization at the molecular and crystal levels, together with conductivity improvement. The basic principles of ECRR, including the metal-selectivity relationship, reaction mechanisms, and electrolyzer design, are introduced. The strategic incorporation of catalytic units within MOFs and the activity modulation through molecular engineering techniques are discussed. Subsequently, this review provides an overview of crystal-level design regarding morphology, coordination defects, and composites. Moreover, the fabrication of both intrinsically and extrinsically conductive MOFs is elucidated, emphasizing the importance of facilitating charge transfer to bolster ECRR performance. Finally, significant prospects about the future challenges and opportunities of MOFs for ECRR are proposed, offering a vision for future research directions.