An isopropanol sensor based on MOF-derived NiO/NiCoxFe2−xO4 porous nanocube with improved response and selectivity

Semiconductor oxides with porous structure have good gas permeability and large reaction surface, which is an important advantage as gas sensing materials. Here, an isopropanol sensor based on PBA-derived spinel NiO/NiCoxFe2−xO4 (x = 0, 0.02, 0.06, 0.10) porous nanocubes were successfully prepared. A series of techniques were used to characterize the crystal structure, morphology and element properties of the products. Gas-sensing measurements show that the doping of Co element can significantly improve the isopropanol-detecting ability of NiO/NiFe2O4. The reason for the improved sensitivity is that cobalt as a dopant can provide more active adsorption sites and the catalytic effect to enhance the gas response. The test results show that NiO/NiCo0.06Fe1.94O4 composite exhibits high response (Rg/Ra=11.2 at 183.5 °C) and selectivity to 100 ppm isopropanol, which is promising for the detection of isopropanol gas. Also, the isopropanol-sensing mechanism of the Co-doped NiO/NiFe2O4 porous nanocubes was discussed. [Display omitted] •An isopropanol sensor based on PBA-derived NiO/NiCoxFe2−xO4 porous nanocubes was successfully prepared.•A variety of techniques were employed to analyze the chemical and structural properties of the samples.•The response of the material to 100 ppm isopropanol was 2.5 times higher than that of NiO/NiFe2O4.•The effects of Co-doping on the improvement of sensing performances were discussed.