Metal organic frameworks (MOFs) are crystalline porous materials formed by the directional assembly of metal nodes and organic ligands through coordination bonds, and the key characteristics are structural designability, ultrahigh surface area, and functional programmability. The structural foundation of MOFs is jointly determined by the geometric configuration of metal nodes and the molecular design of organic ligands. Metal nodes form periodically arranged secondary building units via coordination bonds, where their coordination number and geometry directly govern the topological network of the framework. Organic ligands act as bridging units, with their length, rigidity, and functional groups precisely controlling pore dimensions and surface chemical properties.
The functionality of MOFs stems from their hierarchical pore systems and structure-performance synergy. For gas storage and separation, pore engineering and surface functionalization enable efficient adsorption and selective separation of gas molecules, balancing storage capacity with kinetic efficiency. For heterogeneous catalysis, metal nodes or functionalized ligands serve as active centers for organic and photocatalytic reactions, where pore confinement effects stabilize reaction intermediates and enhance selectivity. For molecular sensing, the cooperative interplay of host-guest interactions and pore electronic properties achieves high-sensitivity detection of trace pollutants or biomolecules. By tuning pore size and surface chemistry, MOFs achieve high drug-loading capacity and pH/temperature-responsive release in drug delivery, alongside biocompatible designs to reduce toxicity. As solid-state electrolytes or electrode materials, their high ionic/electronic conductivity and structural stability enhance energy density and cycling durability in batteries and supercapacitors.