Metal-Organic Frameworks and Composites for Ammonia Capture

초록

The Haber-Bosch process has fueled surging ammonia (NH3) demand for agriculture, pharmaceuticals, and energy, but its toxic, corrosive nature poses challenges for high-pressure storage and transport. Research on metal-organic frameworks (MOFs) for NH3 storage emphasizes their exceptional porosity and functionalization capabilities, enabling high adsorption capacities However, their stability remains a challenge, as many degrade upon NH3 exposure. Recent efforts aim to enhance both NH3 uptake and stability through improved synthesis and post-synthetic modifications. This review highlights recent advances in MOFs for NH3 adsorption, focusing on the key mechanisms involving open metal sites, mu -OH groups, structural defects, and functional surface modifications. The incorporation of unsaturated metal sites and Br & oslash;nsted acidic mu -OH groups significantly improves NH3 binding, while defect engineering introduces additional adsorption sites for increased capacity. Functional modifications, including anion insertion and hydroxyl group functionalization, further boost NH3 adsorption capacity, even in cases of reduced surface area. Emerging MOF composites, such as metal halide-embedded and ionic liquid-loaded materials, demonstrate outstanding NH3 capture performance due to synergistic effects and cooperative interactions. Finally, the future challenges and prospects of MOFs for NH3 capture are discussed, highlighting current obstacles and potential advancements in the field.

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