Role of surfactants on the gas sensing potential of LaFeO3 nanoparticles towards low-concentration ethanol

In this study, LaFeO 3 nanoparticles were synthesized using the hydrothermal method with three different types of surfactants (cationic, anionic, and non-ionic). The products were characterized with various techniques to determine their phase structures, morphologies, sensing abilities, and electrochemical performance. The results indicate that LaFeO 3 prepared with cetyltrimethylammonium bromide (CTAB) as a surfactant (LFO-C) showed a pure orthorhombic perovskite phase with a highly porous surface morphology, and exhibited the largest specific surface area and the lowest impedance among the three materials. The gas-sensing properties of corresponding sensors were also investigated. It is worth noting that LFO-C demonstrated remarkable sensitivity to ethanol at the temperature of 220 °C, with the response reaching 16.1 and a response/recovery time of 35.1 and 25.2 s, respectively. The response of LFO-C is more than twice that of the other two samples with sodium dodecylbenzenesulfonate (SDBS) and polyethylene glycol (PEG) as surfactants. Moreover, LFO-C sensor demonstrated a detection limit of 500 ppb. These findings suggest that CTAB as a cationic surfactant can effectively enhance the gas-sensing performances of LaFeO 3 . Furthermore, the adsorption energy of three samples was calculated by first-principles calculation, and LFO-C possessed strong adsorption capacity for ethanol.