Fabrication of LaFeO3 and rGO-LaFeO3 microspheres based gas sensors for detection of NO2 and CO

In the present report, gas sensing devices based on LaFeO3 and rGO-LaFeO3 were fabricated by a photolithography technique. The X-ray diffraction, Raman spectra and FT-IR results confirm the formation of a perovskite phase and composite. XPS and TEM give the chemical compositions for both products. The higher roughness, greater surface area (62.1 m(2) g(-1)), larger pore size (16.4 nm) and lower band gap (1.94 eV) of rGO-LaFeO3 make it a suitable candidate to obtain high sensitivity. The gas sensing performance of the devices was investigated for various concentrations of NO2 and CO gases at temperatures of 200 and 250 degrees C. It was observed that the rGO-LaFeO3 based device exhibited a high relative response (183.4%) for a 3 ppm concentration of NO2 at a 250 degrees C operating temperature. This higher response is attributed to the large surface area, greater surface roughness, and numerous active sites of rGO-LaFeO3. The gas sensing properties investigated show that rGO-LaFeO3 is an excellent candidate for an NO2 sensor.