Conductometric n-butanol sensor based on Pt-loaded LaFeO3 with 3D hierarchical structure

Abstract

In this work, platinum nanoparticles (NPs) were loaded on the surface of LaFeO3 by wet impregnation method. Various characterization methods were carried out to confirm the microstructure of the samples, and the results showed that the as-prepared LaFeO3 has a 3D hierarchical structure composed of 2D walls of nanoparticles. Gas sensing research shows that the response of the composite loaded with Pt is increased by 2.25 times, and the response/recovery time is reduced from 220 s/214 s to 146 s/131 s, which is a comprehensive reduction of 34 % and 39 %. The material has good selectivity, and the detection limit reaches 100 ppb∼1.38. This enhancement can be attributed primarily to two factors: the formation of a Schottky barrier between the Pt nanoparticles and LaFeO3, where Pt acts as a center of electronic sensitization with a negative charge on the (002) surface of LaFeO3; and the efficient adsorption of oxygen species. First-principle calculations were employed to investigate the adsorption energy of the n-butanol molecule and to identify the advantages of oxygen species adsorption sites on the Pt-LaFeO3 surface compared to LaFeO3 alone. This work not only offers a promising solution for n-butanol sensors with extremely low detection limits but also identifies the most likely forms of gas adsorption and adsorption sites through theoretical calculations, providing a theoretical foundation for the further development of similar sensors.