A NO2 Sensitive MnO2/Graphene Oxide Composite Based Gas Sensor

Nanosized manganese dioxide (MnO2) material has been successfully incorporated into a graphene oxide (GO) sensitive layer. Since this type of heterojunction has never been reported in the literature related to gas sensing, these sensors were prepared, tested, and reported. The morphological properties and composition of the MnO2@GO material have been thoroughly studied via FESEM, XRD, Raman spectroscopy, HR-TEM, and ATR-IR. Gas sensitivity and selectivity towards mainly NO2 and other gases (NH3, CO, ethanol, benzene, and H2) have also been studied. The obtained sensors were exposed to different concentrations of NO2 ranging from 200 ppb to 1000 ppb at 150 °C and under close to real conditions (25% relative humidity and 70% relative humidity). The MnO2@GO sensors have shown a high response of 16.3% towards 1 ppm of NO2 under dry conditions and a higher response of 44% at 70% RH towards the same concentration. Finally, it has also shown a strong sensitivity for NO2.