Gas Sensing Property of MgO Modified LaFeO$_{3}$ Nanocomposites

LaFeO
₃
is a perovskite structure (ABO
₃
) catalytic and p-type semiconductor sensing material, its sensing property for toxic gases is seldom reported. The nanocomposites of LaFeO
₃
and LaFe
_1-x
Mg
_x
O
₃
(x = 0.02, 0.04, 0.06) were prepared by solution based method and their crystal structures were characterized by X-ray diffraction (XRD). The sensing test results showed that the response of LaFeO
₃
to NO
₂
is greatly enhanced by surface modify of MgO from the former 11.90 increased to 891 at the optimum operating temperature of 350°C, and could be contributed to increase of surface active sites supplied by MgO for both oxygen and NO
₂
adsorption and surface reaction. The effect of MgO loading and chemical state on gas sensing have been investigated by temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopic (XPS) analysis.