LPG gas sensor activities of CeO_2-Fe_2O_3 nanocomposite thin film at optimum temperature

摘要

This research paper illustrates the study about the metal oxide composite material and sums up the mechanism of LPG gas sensing. The microwave assisted sol-gel method was applied for synthesizing the ultrafine CeO_2, α-Fe_2O_3 nanoparticles (NPs) and CeO_2-Fe_2O_3 nanocomposites (NCs). The synthesized materials were characterized by means of techniques as XRD, SEM, EDAX and UV-Vis. Spectroscopy. X-ray diffraction patterns of CeO_2 NPs confirmed the cubic structure with crystallite size of 26 nm, and α-Fe_2O_3 NPs revealed the creation of rhombohedral structure with crystallite size of 25 nm. The CeO_2-Fe_2O_3 nanocomposite (NC) has a crystallite size of 10 nm. The SEM image of CeO_2-Fe_2O_3 NC shows small clusters of nanoparticles leading to the establishment of a high mesoporous surface which is useful for gas sensing application. An optical analysis shows that band gap energy lowers from 3.19 eV (E_g-CeO_2) to 1.4 eV (E_g-CeO_2-Fe_2O_3). In this paper, we evaluated the features and mechanism of the LPG sensor centered on pure metal oxides (CeO_2, α-Fe_2O_3) and their composite (CeO_2-Fe_2O_3). The CeO_2-Fe_2O_3 NCs sensor exhibited the highest response of 61.43% with concentration of LPG (24 ppm) at optimum operating temperature 250 °C.