One-step synthesis of CdS hierarchical microspheres and its ethanol sensing property

Abstract

The high concentration (>100 ppm) ethanol gas that CdS sensors detect commonly results in saturation problem. In this work, CdS hierarchical microspheres with the diameter of 5 µm–10 µm assembled with abundant nanosheets are prepared by a facile one-step solvothermal process. The specific surface area of the CdS material was 27.04 m2·g−1, which can provide a certain amount of active sites for the target gas and the adsorbed oxygen. In addition, the sensor fabricated by CdS hierarchical microspheres exhibits enhanced sensitivity for C2H5OH to 10 ppm at the optimum operating temperature of 200 °C. The sensor also shows good repeatability, excellent stability and fast response/recovery time of 2.8 s/4.8 s for C2H5OH to 100 ppm. Meanwhile, the good linear relationship of the sensor under wide concentration range of 10 ppm–500 ppm for C2H5OH demonstrates outstanding humidity resistance. The possible C2H5OH-sensing mechanism of CdS hierarchical microspheres is discussed on the basis of XPS analysis.