In-situ growth of CuO nanorods on sensing electrodes and their gas sensing properties of VOCs

The CuO nanorods were in-situ grown on sensing electrodes by a chemical bath method for the detection of volatile organic compounds (VOCs). The synthesized material was characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR). The CuO nanorods, with lengths of 100–150 nm and diameters of 35–55 nm, were uniformly formed into a thin film on the electrode surface, with a thickness of approximately 1 μm. The gas test results demonstrated that the sensor achieved a peak response of 1.32 for formaldehyde at 200 °C, and a response of 1.92 for ethanol at 175 °C. At a concentration of 50 ppm, ethanol and formaldehyde at an operating temperature of 200 °C exhibit short response/recovery times of 28 s/48 s for ethanol and 45 s/62 s for methanol, respectively, coupled with good reproducibility. Moreover, the sensor exhibited a power-law response to varying gas concentrations and showcased superior selectivity in the VOCs gas detection. This in-situ growing CuO of our work provides a facial gas sensing material fabricated method.