ZIF-8, Zn(NA) and Zn(INA) MOFs as chemical selective sensors of ammonia, formaldehyde and ethanol gases

In this paper we report fabrication and deployment of zinc with 2-methylimidazole (ZIF-8), nicotinic acid (Zn(NA)) and isonicotinic acid (Zn(INA)). These Metal Organic Frameworks (MOFs) are applied as an advanced chemical capacitive sensor for the detection of ammonia (NH3), formaldehyde (HCHO) and ethanol (C2H5OH) at room temperature. These MOFs were characterised by X-ray powder diffraction (XRD), scanning electron microscope (SEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA) and FTIR. The specific surface area of MOFs was carried out by Brunauer–Emmett–Teller (BET) analysis and the pour size analysis by the Barrett, Joyner, Halenda (BJH) method. Gas sensing studies were carried out with two probe static method. All compounds exhibit reasonable selectivity with ammonia, formaldehyde and ethanol gases. Zn(NA) has shown good Response towards ammonia even at 10 ppm concentrations and towards ethanol at 50 ppm. While ZIF-8 shows higher e towards formaldehyde even at 5 & 10 ppm. Response and recovery times were determined using transient response analysis and stability with time is determined. •Fabrication of ZIF-8, Zn(NA) and Zn(INA) MOFs using low cost chemical route method.•Micro-structural, morphological and gas sensing characterization are performed.•These MOFs have large pores, rough surface and average particle size 1.5–4.5 μm.•Zn-MOFs are good chemical gas sensors towards NH3, formaldehyde and ethanol at RT.•Zn(NA) is shown best response towards 10 ppm of NH3 at RT.