Publication

Abstract : NO2 is an air pollutant that is hazardous for human beings. This work reports the detection and fast prediction of NO2 at room temperature by molybdenum carbide-reduced graphene oxide (Mo2C-rGO) composite. The Mo2C nanoflakes, graphene oxide nanosheets, and Mo2C-rGO were synthesized using facile chemical routes. The 2-D morphologies of the nanomaterials were ensured by a field emission scanning electron microscope with an average lateral dimension of 800 nm and 40 μm of Mo2C and rGO, respectively. The band gap of the Mo2C-rGO composite (1.63 eV) was found to be lower compared to intrinsic Mo2C (1.75 eV). The valley points at 1045 and 880 cm−1 of the Fourier transform infrared spectroscopy images represent the coexistence of the pristine materials in the composite. Next, Mo2C, rGO, and Mo2C-rGO composites were tested for different concentrations (25–100 ppm) of NO2 at room temperature, and the response of the composite was found to be maximum (−4.1% to −15.9%). The response and recovery times of the sensor were found to be 3011 and 1633 s for 25 ppm NO2, which are longer and undesirable. Hence, a transient analysis coupled with the cantor pairing method was employed to successfully reduce the prediction time of NO2 to 200 s. The Mo2C-rGO composite exhibited a response of 0.2%, 0.3%, and 4% to 100 ppm of NH3, CO, and 80% relative humidity, thereby establishing high selectivity toward NO2.