Facile Synthesis of Mn-Doped CuO Nanoflower Spheres and Their Enhanced Sensing Performance for Isopropanol

In this work, the Mn-doped copper (II) oxide (CuO) nanoflower spheres (CuO-1% Mn nanoflower spheres) are synthesized through a facile low-temperature hydrothermal method. The as-prepared sample is characterized by X-ray powder diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman and Brunauer–Emmett–Teller (BET) analysis. The results indicate that the nanoflower spheres with diameters of 5– $10 \mu \text{m}$ are assembled by a huge number of nanosheets. In addition, Mn ions are uniformly doped into the CuO nanoflower spheres. The surface area of the CuO-1% Mn nanoflower spheres is 33.079 $\text{m}^{{2}}$ /g. Under the optimized temperature of 235 °C, when the Mn doping amount is 1%, the CuO-1% Mn nanoflower spheres exhibit the best sensing property toward isopropanol, the response of which is almost 11.5 times higher than that of pure CuO. In a wide range of 1–100 ppm, the CuO-1% Mn nanoflower spheres exhibit linear response in isopropanol detection. The doped sample also exhibits excellent selectivity, repeatability, and durability. It is believed that the doping of Mn ions would be the reason of the improvement of sensing properties. Due to the doping introduced more defects and spillover effect, more oxygen anions would be generated and more isopropanol molecules can be oxidized on the surface of the CuO-1% Mn nanoflower spheres. It is believed that the product has great application potential in isopropanol detection.