Modified WO3 nanosheets by N-GO nanocomposites to form NO2 sensor

In this work, WO3 nanosheets were synthesised and decorated with different percentages of N-GO nanocomposites to study gas sensing assets. The X-ray diffraction (XRD) and Raman spectra showed fine crystal quality. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) illustrated nanosheets morphology for WO3 and confirmed its decoration. The variation of the sensor electrical resistance was studied at various gas concentrations in the range of temperature intervals. The optimal operational temperature was 200 °C. The optimum response signal and recovery time for WO3–N-GO 6% at 200 ppm concentration were 90 s and 205 s, respectively. The selectivity of the WO3–N-GO samples was 53%, 46% and 60% for WO3–N-GO 3%, WO3–N-GO 6% and WO3–N-GO 9%, respectively at 200 °C. The highest response was found for WO3–N-GO 9% to NO2 (58%) and WO3–N-GO 6% to CO (28%) at 200 °C. Therefore, by selecting the optimum percentage of N-GO nanocomposites, the sensors can be fabricated with the highest response to NO2 or CO