Metal–Organic Frameworks for Electrocatalytic CO2 Reduction into Formic Acid

Metal–organic frameworks (MOFs) are used in catalysis due to their high specific surface area and porous structure. The dispersed active sites and limited reaction space that render MOFs have the potential for highly selective electrocatalytic CO2 reduction reaction (ECO2RR). Meanwhile, formic acid (HCOOH) is attracting attention as a liquid product with high economic benefits. This review summarizes the MOFs and their derivatives applied for ECO2RR into HCOOH products. The preparation methods of MOFs as electrocatalysts and their unique advantages are discussed. A series of MOFs and MOF derivatives obtained by electrochemical reduction or carbonization processes are highlighted, including metal nanomaterials, carbon-based nanocomposites, single-atom catalysts, and bimetallic nanocomposites. Depending on the MOF building units (metal ions and organic linkers) and the reaction conditions of derivatization, MOF-based catalysts exhibit rich diversity and controllable modulation of catalytic performance. Finally, the challenges encountered at this stage and the future research directions of MOF-based catalysts are proposed.