Strategies for MOF Functionalization in Pyrotechnics and Propellants: Internal and Interfacial Approaches.

Metal-organic frameworks (MOFs) provide a modular platform for controlling energetic performance, ignition, combustion, thermal stability, and safety, but the structural origin of these effects is often difficult to distinguish from interfacial contributions in multicomponent pyrotechnic formulations. This review organizes MOF functionalization according to the dominant level of modification: internal-framework functionalization (IF), including linker, metal-node, pore, counterion, and guest engineering, and external/interfacial functionalization (EF), including interfaces with metallic or boron fuels, carbon materials, oxidizers, and polymer matrices. Only systems in which intact MOFs are introduced into the energetic formulation are considered, and representative studies are compared through structure-mechanism-response relationships. The analysis shows that IF primarily governs intrinsic chemical reactivity, redox pathways, energetic content, initiation mode, and sensitivity, whereas EF determines how efficiently this functionality is delivered through heat, mass, and charge transfer and spatial contact. Reported improvements in decomposition, ignition, combustion, and pressure generation are strongly condition-dependent and may involve trade-offs in sensitivity, compatibility, or active-fuel fraction. Functionalization should therefore be selected according to the rate-limiting stage of the target formulation, with matched controls and formulation-level validation required for mechanistic interpretation and practical design.