Rapid and Highly Sensitive Detection of Formaldehyde at Room Temperature Using Rgo/Wo3 Nanocomposite

Formaldehyde (HCHO) is an indoor toxic volatile compound (VOC) gas, which can harm respiratory   tract of human beings when a person is in exposed to low concentration of HCHO for a long time. In this study, a HCHO sensor with high response and low detection limit based on rGO/WO 3 ( rGW ) nanocomposite was successfully synthesized by hydrothermal method. Experimental results depict that the average response value of rGW2 is about 2000 towards 500 ppm HCHO at room temperature, the response/recovery time is 2.8 s/1.7 s for HCHO at 0.5 ppm and the low detection limit is 0.5 ppm. Moreover, rGW2 exhibits excellent selectivity and good stability. Compared to WO 3 , the combination of rGO with WO 3 can increase the oxygen vacancy on WO 3 surface and afford more active sites for capturing HCHO. Furthermore, the formation of electron depletion layer and potential energy barrier between rGO and WO 3  increase intrinsic impedance of rGW nanocomposite to further enhance the property of HCHO sensor based on rGW. This study indicates that the combination of rGO with WO 3 can efficiently enhance the property of WO 3 -based HCHO sensor at room temperature, which is conducive to the application of metal oxide semiconductor in field of gas sensors.