Enhanced acetone sensing performance of CeO2-ZnO at low temperature and its photo-excitation effect

Abstract

In this work, pure ZnO and CeO2-ZnO nanomaterials with CeO2 doping amounts of 6.04 wt%, 7.04 wt% and 8.04 wt% were synthesized by a one-step hydrothermal method. XRD, SEM, N2 adsorption-desorption measurement, XPS and UV–vis spectroscopy were carried out to characterize the morphological and crystallization information of the material. Gas sensing measurements of CeO2-ZnO nanomaterials based gas sensor were conducted, it was found that 7.04 wt% CeO2-ZnO had the best gas sensing property with shorter response and recovery time (4 s/3 s)and higher response (61.92) which is more than five times than that of pure ZnO to 100 ppm acetone at 75 °C. Moreover, the sensor based on 7.04 wt% CeO2-ZnO had low detection limit of 2.71 to 2 ppm acetone at 75 °C. With the irradiation of visible light, 7.04 wt% CeO2-ZnO shows the response up to 104.36 to 100 ppm acetone at 75 °C which is 68% higher than that without visible light, indicating that the sensor response is significantly enhanced by photo-excitation effect. Furthermore, the sensing mechanism of sensors and the mechanism of photo-excitation were detailedly discussed.