Nanoarchitecturing of Bimetallic Metal‒Organic Frameworks for Emerging Applications in Quartz Crystal Microbalance Gas Sensors.

Metal‒organic frameworks (MOFs) are promising materials for advanced sensors because of their large surface area, high porosity, and compositional and structural versatility. The incorporation of a secondary metal center to form bimetallic MOFs can significantly enhance sensor performance by increasing the number of adsorption sites for gas molecules, enhancing charge transfer, and improving structural stability. Additionally, the tunable structure, composition, and porosity of bimetallic MOFs allow for the design of highly selective sensors tailored to specific gases. However, their low conductivity and thermal stability limit their application in traditional chemiresistive sensors. Instead, bimetallic MOFs are well suited for mass-sensitive gas sensors, such as quartz crystal microbalance (QCM) gas sensors, which operate at room temperature and rely on physical or chemical interactions. This review highlights recent advances in the exterior and interior nanoarchitectural control of bimetallic MOFs and their emerging applications in QCM sensors for various gas detection methods, along with the underlying sensing mechanisms. This study concludes with an overview of the challenges and future research directions in the synthesis and application of these materials for QCM gas sensors.