Synthesis and characterization of Zn based bi metallic micro porous MOF composites for effective formaldehyde sensing at room temperature

In the present work, we fabricated 1:1 bimetallic ZnCu(NA); ZnCd(NA); and ZnCo(NA) metal organic frameworks (MOFs) using nicotinic acid (NA) as organic linker by solvothermal method. Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, X-Ray Photoelectron Spectroscopy (XPS), and scanning electron microscopy (SEM) were used to describe all bimetallic MOF topologies. These compounds were used to develop chemiresistive sensor devices for sensing of formaldehyde vapor at room temperature. Drop-casting method was used to make the sensing device on a glass plate with silver electodes. The resulting bimetallic sensors exhibited excellent sensitivity, good linearity and more stability in the detection of formaldehyde at 1 to 50 ppm concentrations. ZnCo(NA) exhibited more response towards formaldehyde vapor than other bimetallic MOFs. Transient response analysis was used to determine response and recovery times, as well as stability over time. These findings prove the application prospects of bimetallic Zn/Cu, Zn/Cd and Zn/Co MOFs in the selective and sensitive detection of formaldehyde at room temperature.