Metal-organic frameworks for NH3 adsorption and separation

Abstract

Ammonia (NH3) is not only an air pollutant but also a versatile and favourable chemical with widespread applications in human life. As a key component of nitrogen fertilizers, it plays a crucial role in improving crop yields. Additionally, NH3 serves as a hydrogen carrier and working fluid, contributing to the energy transition process. Given the diverse roles of NH3 and the varying requirements for adsorbents across different application scenarios, the rational design and selection of adsorbent materials are paramount. Metal-organic frameworks (MOFs) have emerged as promising adsorbent candidates due to their highly tunable structure and functionality, which can precisely match the characteristics required for NH3 adsorbents in multiple application scenarios. This review provides a comprehensive evaluation of NH3 adsorbents, delves into the stability characterization of MOFs under NH3 atmospheres and the underlying adsorption/degradation mechanisms. Additionally, we discuss the existing methods used to probe the host-guest interactions between MOFs and NH3. Finally, this study systematically summarizes the latest advancements of MOFs as NH3 adsorbents and classifies them according to the different requirements imposed by the varying roles of NH3. This review provides theoretical support for the design of more efficient NH3 adsorbents in the future.