Rapid and Efficient Detection of NH3 at Room Temperature Using CuO/WS2 Nanohybrids

This work introduces the fabrication of room temperature NH ₃ gas sensors based on CuO/WS ₂ nanohybrids by direct mixing WS ₂ nanosheets and CuO nanocubes in an ultrasonic bath. The ultrathin WS ₂ nanosheets (~5 nm) overlap with each other, and a proportion of CuO nanocubes embedded in the WS ₂ matrix can be observed in the hybrids. The CuO/WS ₂ nanohybrids demonstrate an excellent NH ₃ sensing performance at room temperature, which not only inherit the merits of rapid response ability of WS ₂ nanosheets, but also partially maintain the high sensitivity of CuO nanocubes. Measurements indicate that the CuO/WS ₂ nanohybrids with a mass ratio of 2:1 exhibit a relative high response to NH ₃ (60.7%, at 60 ppm), with good reproducibility, stability and selectivity, which can be attributed to the cooperative effect of efficient gas adsorption of CuO nanocubes and the fast carrier transportation of WS ₂ nanosheets. Furthermore, the NH ₃ sensing performance of 2:1 CuO/WS ₂ sensor on a PET substrate remains stable after 200 bending cycles, indicating a potential for the development of flexible devices.