Gas-sensing properties of perovskite La0.875Ba0.125FeO3 nanocrystalline powders

La0.875Ba0.125FeO3 nanocrystalline powders have been prepared by a sol–gel method. The structure, conductance and gas-sensing properties were investigated. La0.875Ba0.125FeO3 crystallizes as a perovskite phase with the orthorhombic structure. The La0.875Ba0.125FeO3 based sensor shows good sensitivity and selectivity to alcohol gas. The highest sensitivity to 500 ppm alcohol gas reached was 58 at 170 °C. The adsorption of O2 on the La0.875Ba0.125FeO3 (0 1 0) surface was studied with the first-principles calculation based on the density functional theory. The results show that the surface states are near the Fermi energy level and that the Fe ion plays an important role in the process of oxygen adsorption, which affects the gas-sensing properties.

Research Highlights
► La0.875Ba0.125FeO3 crystallizes as a perovskite phase with orthorhombic structure.
► La0.875Ba0.125FeO3 based sensor shows good sensitivity and selectivity to alcohol.
► The states of the La0.875Ba0.125FeO3 (0 1 0) surface are mainly caused by Fe 3d orbit.
► The surface Fe ions dominate the oxygen adsorption processes.