Reduced graphene oxide-cuprous oxide composites for low concentration ozone detection

In this research, cuprous oxide (pristine Cu2O) and rGO (reduced graphene oxide)-doped Cu2O were prepared using a simple synthetic route and adopted as sensitive materials for ozone detection. The microstructural, morphological and compositional properties of as-prepared samples have been analyzed by several characterization techniques including X-ray diffraction (XRD), High resolution transmission electron microscopy (HRTEM), Energy dispersive spectrometer (EDS), UV-Visible spectrophotometer (UV-vis), Multi-functional field emission scanning electron microscope (FESEM), X-ray Photoelectron Spectroscopy (XPS) and Brunauer-EmmettTeller (BET). Meanwhile, the sensing features of as-prepared samples have been investigated carefully and the asprepared 0.5 wt% rGO-Cu2O exhibited best ozone sensing properties, such as high stability, sensitivity and selectivity. It can be found that the response value of 0.5 wt% rGO-Cu2O-based sensor towards 20 ppb ozone and 1 ppm ozone were 9.2/1734, respectively, and the corresponding response and recovery times were 11/64 s and 11/411 s, respectively. More importantly, the detection limit of the 0.5 wt% rGO-Cu2O sensor was as low as 0.1 ppb. Furthermore, the possible mechanism for the enhanced sensing performance of the as-prepared rGO-Cu2O has been discussed.