Preparation and Gas Sensing Characteristics of Nanoparticulate p‐Type Semiconducting LnFeO₃ and LnCrO₃ Materials

Abstract

Nanoparticulate perovskite‐type LnBO3 (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; B = Cr, Fe) oxides are prepared by polyol‐mediated synthesis. X‐ray diffraction is used to confirm the structure of the materials, and scanning electron microscopy is applied to image the sample morphology. The powders are used for the preparation of suspensions that are deposited as thick films on comb‐type Pt electrodes on alumina substrates. Electrical characterization is performed by using high‐throughput impedance spectroscopy. The materials exhibit p‐type semiconductor behavior, and their sensitivity towards H2, CO, NO, NO2, and propylene in a temperature range from 200 to 500 °C is analyzed. In addition, the time‐resolved response of the LnFeO3 materials is investigated. A correlation between the Ln–O binding energy and the sensing properties is observed.

Electrical conductivity and thermopower of (1 − x) BiFeO3– xBi0.5K0.5TiO3(x = 0.1, 0.2) ceramics near the ferroelectric to paraelectric phase transition

“…[33][34][35][36][37] The electrical conductivity of these materials has previously been modelled with success by a mass action type treatment of point defect equilibria. A mass action type model adapted for 0.8BFO and 0.9BFO is introduced here based on the approach presented by Mizusaki et al 35 for LaFeO 3 .…”

“…27,28,32 P-type (in air) and n-type (reducing conditions) semiconductor behaviour has previously been reported for several related Fe-containing perovskites, including La 1Àx Sr x FeO 3Àd [33][34][35] and LnFeO 3 (Ln = Pr, Nd, Sm, Eu and Gd). 36,37 In these materials the electronic conductivity is strongly linked to polaron hopping and the oxidation state of Fe, which is strongly dependent on the partial pressure of oxygen ( p(O 2 )).…”

Self-propagating combustion synthesis and synergistic photocatalytic activity of GdFeO3 nanoparticles

“…They have potential for various applications such as solid oxide fuel cells, sensors, magnetooptic materials, electrode materials, catalysts, and magnetic resonance imaging (MRI) in biomedicine [12][13][14][15]. Recently, rare-earth orthoferrite compounds with perovskite structure [16][17][18][19], such as SmFeO 3 , LaFeO 3 , GdFeO 3 , EuFeO 3 , NdFeO 3 , PrFeO 3 , and YFeO 3 , have received increasing attention and been applied as photocatalysts. More importantly, it is interesting to note that some perovskite-type Fe-based materials have been confirmed as heterogeneous Fenton-like catalysts.…”

Advances in high throughput screening of gas sensing materials

“…In addition the synthesis of various volume-doped materials was also possible. A detailed description of the reaction procedure can be found in [15,19].…”