Room temperature NO2 sensing performance enhancement of VO2(B) composited rGO structure

The VO2(B)/rGO composite structure was proposed to improve the gas sensitivity response of VO2(B) at room temperature (25 degrees C) through replacing the homojunctions by heterojunctions. Pure VO2(B) nanorods were synthesized and composited with flake-shaped rGO by hydrothermal method. The nanorods show smooth surface and the average length is about 1 mu m, the average width is about 100 nm. The composition of the samples is VO2(B) and is not affected by the rGO-additive during synthesis.VO2(B) nanorods were connected by sheet-like wrinkled graphene. The gas-sensing measurement of sensor with a NO2 concentration range of 1-5 ppm at room temperature was carried out. The response value of VO2(B)/rGO sensor to 5 ppm NO2 is improved by 23% and can reach up to 1.63 with increasing the rGO concentration. The sensor also shows good selectivity and reproducibility to NO2. The improvement of room temperature sensing performance is related to the multiple hetero-junctions formed by the rGO nanosheets. The mechanism of improving the gas sensitivity of the VO2(B)/rGO was further discussed. These results are significance for enhancement the performance of room temperature NO2 sensor.