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

Abstract

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 m² 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 °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 °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.