Recent progress of gas sensors based on metal oxide composites derived from bimetallic metal-organic frameworks

Gas sensors based on semiconductor metal oxides (SMOs) composites have been widely applied into environmental monitoring, medical diagnosis, industrial production, and other fields. However, it is not only necessary but challengeable to further enhance the sensing performance including high response, outstanding selectivity, low limit of detection, fast response/recovery time, excellent humidity resistance, and good long-term stability. Bimetallic metal-organic frameworks (BMOFs) as excellent templates synthesize SMOs composites with various mesoporous structures and adjustable compositions, which is beneficial for enhancing the sensing performance further. Moreover, tremendous efforts have been made in synthesizing metal oxide composites with different morphology and compositions by employing BMOFs as self-sacrificing templates and precursors, and obtained remarkable achievements in gas-sensing applications. However, there are few reviews focusing on the such promising area. In this review, the recent progress of gas sensors based on SMOs composites derived from BMOFs have been systematically summarized. Firstly, the sensing performance parameters, sensing mechanism and strategies for improving the sensing performance are discussed. Then, the BMOFs fabricated via direct synthesis and ion-exchange methods derived SMOs composites with various structures and compositions for gas sensing applications are comprehensively summarized, respectively. In addition, the BMOFs-derived spinel structure-like SMOs based gas sensors with advanced performance are meticulously reviewed. Finally, the challenges and prospects in the field of SMOs derived from BMOFs for gas detection applications are presented. This review will open a new door for the subsequent development of advanced SMOs materials derived from BMOFs in gas sensing applications.