Novel Co3O4-CuO-CuOHF porous sheet for high sensitivity n-butanol gas sensor at low temperature

In this study, porous sheet-like nanostructured Co3O4-CuO-CuOHF composites with great n-butanol sensing properties were synthesized by the biotemplate method and hydrothermal method. The effect of various contents of Co3O4-CuO-CuOHF sensor performance was systematically investigated, in which the best performance was achieved for the composite with 0.03 g Co3O4 addition. The response of the best content Co3O4-CuO-CuOHF composite sensor to 100 ppm n-butanol at 180 ℃ is 120, which is 8 times higher than that of the CuO-CuOHF sensor. The composite sensor has excellent selectivity for n-butanol and responds 3.75–25 times higher to n-butanol than other target gases. It is detectable up to 500 ppb n-butanol and has potential promise for low concentration detection. Furthermore, it has outstanding stability and resistance to humidity. The gas sensing mechanism was analyzed by UV–visible diffuse reflectance spectroscopy, EPR oxygen vacancies and X-ray photoelectron spectroscopy, which indicated that the abundant oxygen vacancies, the physical adsorption of polar hydroxyl bonds, the electronegative fluorine substitution and the special microstructure of the composite contributed to its gas-sensitive performance.