Rapid and highly sensitive detection of formaldehyde at room temperature using rGO/WO 3 nanocomposite

Formaldehyde (HCHO) is an indoor toxic volatile compound (VOC) gas, which can harm respiratory tract of human beings when a person is exposed to low concentration of HCHO for a long time. In this study, an 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 rGW is about 2000 towards 500 ppm HCHO at room temperature, the response/recovery time is 2.8 s/1.7 s for HCHO at 500 ppb and the low detection limit is 500 ppb. Moreover, rGW 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.