Unlocking MOF Potential in DMFC Systems: A Critical Analysis of Structural Innovations and Future Perspectives

Advancing direct methanol fuel cells from the lab to market remains constrained by major challenges, such as undesired methanol permeation across electrolyte membranes and limited anode catalytic activity associated with sluggish methanol oxidation. These challenges lead to reduced efficiency and durability and hinder commercialization. Metal–organic frameworks (MOFs), constituting a category of structures with remarkable porosity and tunable and chemically versatile materials, offer promising solutions to both membrane and electrocatalyst limitations in DMFC systems. This account critically examines recent progress in MOF-based approaches for DMFCs, with particular emphasis on their dual functionality. First, the incorporation of MOFs into PEMs is discussed, highlighting their ability to enhance proton conductivity while reducing methanol permeability through mechanisms such as acid–base functionalization, pore confinement, and improved water retention. Second, MOFs are reviewed as electrocatalyst supports or precursors, particularly in enhancing MOR activity, CO tolerance, and long-term stability via synergistic interactions, heteroatom doping, and structural templating. Performance metrics like proton transfer, methanol permeability, and power output are critically compared across studies to demonstrate the impact of MOF integration. Structural design strategies, including postsynthetic modifications and hybrid composite formation, are discussed to elucidate key structure–function relationships. Furthermore, sustainability considerations, such as green synthesis, reduced noble metal loading, and lifecycle impact, are emphasized. By bridging material innovation with device-level challenges, this review outlines future research directions for optimizing MOF–polymer and MOF–catalyst interfaces. The insights provided aim to guide researchers toward developing high-performance, durable, and scalable MOF-enabled DMFC technologies.