Highly sensitive ethanol sensor based on Ce-doped WO₃ with raspberry-like architecture

This work reported a highly sensitive ethanol sensor assembled from raspberry-like hierarchical Ce-doped WO₃ nanoparticles. The Ce-doped WO₃ nanoparticles doped with different contents (0, 2, 4 and 8 at%) of Ce were synthesized by a facile hydrothermal method. The crystalline structure and the micromorphology of Ce-doped WO₃ nanoparticles were measured by x-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), respectively. The x-ray photoelectric spectroscopy (XPS) and transmission electron microscopy (TEM) attached with energy-dispersive spectroscopy (EDS) confirmed the elemental distribution and the chemical state of surface elements. Comparison between the pristine and Ce-doped WO₃ samples revealed that the doping of Ce on WO₃ can powerfully improve the response ability to ethanol. As the doping content of Ce element was 4 at%, the sensor exhibited optimal response to ethanol in the range of 0.1–50 ppm at the working temperature of 350 °C. The response can achieve a high value of 12.3 for detecting 1 ppm ethanol with a fast response/recovery (6s/6s). Impressively, the sensor still maintained a good response (8.1) to ethanol even at sub-ppm level (0.1 ppm ethanol). This work will pave a platform for design and development of highly sensitive ethanol sensors. (paper)