Tuning the functionality of metal-organic frameworks (MOFs) for fuel cells and hydrogen storage applications

Metal-organic frameworks (MOFs) are porous crystalline materials with exceptional properties. The tremendous synthetic tunability of MOFs has emerged to be beneficial for many applications. This review study discusses the roles of MOFs in hydrogen fuel cell technology, including the synthesis of oxygen reduction catalysts, hydrogen storage materials, and ion carriers for polymer electrolyte membranes (PEMs). Various chemical modification approaches have been identified, namely: (1) confinement of guest species into the pores of MOFs, (2) modification of the organic ligands with functional groups, and (3) carbonization of MOFs. The tunable properties of MOFs have offered an improvement toward their desired application. The primary properties are surface area, which correlates with the availability of active sites that lead to an improvement in electrochemical performance. Finally, the outline concerning commercializing fuel cell technologies with MOFs is tabulated along with a future perspective in addressing some of the current limitations in the studies.