SO2 and H2S Sensing Properties of Hydrothermally Synthesized CuO Nanoplates

Abstract

CuO nanoplates were synthesized by a facile hydrothermal method for a SO2 gas-sensing application. The synthesized materials were characterized by field-emission scanning electron microscopy (FE-SEM), powder x-ray diffraction (XRD), Raman spectroscopy, and photoluminescence spectroscopy. Gas-sensing characteristics were measured at various concentrations of SO2 and H2S at 200–350°C. The results showed that rectangular CuO nanoplates with an average size of approximately 700 × 500 × 30 nm3 were synthesized. FE-SEM and XRD analyses also depicted that the nanoplates were polycrystalline with an average crystal size of 12.85 nm. Gas-sensing measurements demonstrated that the synthesized CuO nanoplates exhibited p-type semiconducting behavior, where the sensor resistance increased upon exposure to H2S and decreased when exposed to SO2. The sensor showed a considerably higher response to SO2 than to H2S in the measured concentrations ranging from 1 ppm to 10 ppm, suggesting that the CuO nanoplates are suitable for high-sensitivity SO2 sensing. We also clarified the sensing mechanism of the CuO nanoplate-based SO2 sensors.