Novel p-n heterojunction of BiVO4/Cu2O decorated with rGO for low concentration of NO2 detection

NO2 is a toxic gas that can cause photochemical smog, acid rain and ozone layer depletion. The reduced graphene oxide (rGO) decorated nanocomposites of semiconductor metal oxides (MOS) as sensing materials of NO2 sensors have received much attention. Here, BiVO4/Cu2O/rGO nanocomposite was successfully prepared by a facile solvothermal method and thermal reduction method. The gas-sensing test indicates that the response of optimum nanocomposite to 1 ppm NO2 is 8 times higher than the pure BiVO4 and 5 times higher than the p-n heterojunction of BiVO4/Cu2O, respectively at 60 degrees C operating temperature. The response time and recovery time also shortened compared to pure BiVO4 and BiVO4/Cu2O composite, and this composite has better stability for detection of NO2, which benefits from the superimposed effect of p-n heterojunction formation and rGO decoration. This work can provide reference for improving the sensing properties of metal oxide semiconductor composites for detection of NO2.