Synthesis of LaFeO3 catalytic materials and their sensing properties

LaFeO3 is a p-type semiconductor catalytic material of perovskite structure (ABO(3)). Its magnetic and photocatalytic properties have been widely investigated, but the gas sensing properties are seldom reported, especially for toxic and noxious gases of NO2 and CO. The nanocomposites of LaFeO3 and LaFe1-x Mg (x) O-3 (x = 0.02, 0.04, 0.06) were prepared by various methods of the wet chemical process and their exact composition, crystal structures, grain sizes, specific surfaces, morphology and the electronic interaction between components were characterized by EDX, XRD, BET, SEM and XPS analysis. The sensors based on these nanocomposites have been fabricated to examine the sensing responses to gases, and the results show that these sensors exhibited high response to both oxidizing gas (NO2) and reducing gas (CO), and the response was greatly enhanced by the surface modification of MgO. The additive method, amount of additives, and their effects on the LaFeO3 structure and gas response have been analyzed and discussed by temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopic (XPS) analysis.