Excellent sensing platforms for identification of gaseous pollutants based on metal-organic frameworks: A review

There are a variety of pollutants in the air, in recent decades, some of the pollutant gas content has exceeded the standard, seriously endangering human health as well as the living environment, and the development of effective pollutant gas sensors is imminent. Compared with common gas sensors, gas sensors based on metal-organic frameworks (MOFs) have the advantages of structural tunability, large specific surface area, and high porosity. MOFs are a kind of organic-inorganic hybrid crystalline materials with periodic molecular network structures formed by the self-assembly of organic ligands and metal ions through coordination bonds. By introducing new functional groups in MOFs, functionalized MOFs sensors can be designed to recognize specific gases. Gas sensors based on MOFs generally have efficient sensing efficiencies. In the current review describing MOFs gas sensors, the classification and summary of MOFs sensors for sensing different gases are missing. This review presents MOFs-based gas sensors according to different sensing mechanisms. Additionally, recent sensors for sensing different gaseous pollutants are discussed. MOFs sensors for different gas pollutants are categorized and discussed concerning their preparation, performance, and mechanism. Finally, the areas of scientific development as well as future challenges and prospects for MOFs gas sensors are summarized.