Acetone sensing characteristics of TiO2-LaFeO3 nanocomposites

Abstract

To enhance the acetone sensing capabilities of LaFeO3 nanoparticles for practical applications in breath analysis, commercial n-type rutile TiO2 nanoparticles were utilized as additives and directly mixed with LaFeO3 nanoparticles synthesized via a sol–gel method. The obtained TiO2-LaFeO3 nanocomposites were characterized by XRD, SEM, BET, and XPS. Compared to pure LaFeO3 nanoparticles, the resulting TiO2-LaFeO3 nanocomposites exhibited higher surface reactivity, as evidenced by their larger specific surface areas and higher oxygen vacancy contents. The introduction of TiO2 also facilitated the formation of p-n heterojunctions, which enhanced the regulation of acetone molecules on internal carrier conduction within the nanocomposites. Therefore, the TiO2-LaFeO3 nanocomposites demonstrated improved acetone sensing performance, including higher vapor response values, selectivity, and faster response/recovery speeds. Among the series of nanocomposites, those with an addition of 10 wt% TiO2 exhibited the highest vapor response value (37.3 to 100 ppm) and the greatest selectivity against methanol and ethylene glycol at the prime operating temperature of 144 °C.