Vertically Aligned WO3–CuO Core–Shell Nanorod Arrays for Ultrasensitive NH3 Detection

Vertically aligned WO 3 –CuO core–shell nanorod arrays for NH 3 sensing are prepared. The sensor is fabricated by preparing WO 3 –CuO nanorod arrays directly on silicon wafer with interdigital Pt electrodes. The WO 3 –CuO nanorod arrays are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The sensor based on the vertically aligned WO 3 –CuO nanorod arrays exhibits ultrasensitive NH 3 detection, indicating [Formula: see text]-type behavior. The optimum sensing temperature is found to be about 150[Formula: see text]C. Both response and recovery time to NH 3 ranging from 50[Formula: see text]ppm to 500[Formula: see text]ppm are around 10–15[Formula: see text]s. A possible NH 3 sensing mechanism of the vertically aligned hybrid nanorod arrays is proposed.