Synthesis of CuO–CdS composite nanowires and their ultrasensitive ethanol sensing properties

In this paper, CuO–CdS composites were synthesized by a facile two-step solvothermal method. The composite materials were characterized by a series of systematical measures, such as X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. Through detailed experiments, it was observed that the shape of the as-prepared materials could be tailored by varying the CuO content in composites. The experimental results manifested that CdS decorated with 0.05 at% CuO presents superior performance including response/recovery speed, detection limit, optimum operating temperature, and sensitivity in comparison with pure CdS. The possible mechanisms of enhanced sensing properties were discussed in detail. At the interface of the two different material surfaces, the capacity of surface-adsorbed oxygen was elevated, which can be attributed to the formation of the p–n heterojunction between CdS and CuO. In conclusion, the functionalization of CuO with CdS may be a promising method to enhance gas-sensing properties.