Improvement in the performance of In2O3 ethanol sensor by perovskite-type LaFeO3 modification and sensitivity mechanism analysis

In this paper, LaFeO3/In2O3 composites are prepared by hydrothermal methods. The microstructure and crystal structure of LaFeO3/In2O3 composites were characterized. The results of gas-sensitive testing show that the LaFeO3/In2O3 composite gas sensor has a higher response than pure In2O3. The LaFeO3/In2O3 sensor made up of 0.01 g LaFeO3 shows a response of 147 at 220 °C to 100 ppm ethanol gas. It was found that LaFeO3 could enhance the gas-sensitive properties of In2O3. The surface properties of LaFeO3 and In2O3 are calculated and analyzed by the first principal method. The sensitivity mechanism of LaFeO3 enhancing the properties of the In2O3 sensor is analyzed from the aspects of adsorbed oxygen, heterojunction, and LaFeO3 catalyst. The LaFeO3/In2O3 sensor has a better gas-sensitive performance than the In2O3 sensor because of the large amount of oxygen adsorption, the special Fermi level effect of heterojunction, and the catalytic effect of LaFeO3 on the redox reaction. •LaFeO3/In2O3 nano-materials are synthesized by a hydrothermal method.•The doping of LaFeO3 increases the absorbed site of In2O3 nano-material.•The performance improvement is analyzed by absorbed oxygen and heterojunction.•Catalytic effect of perovskite-type LaFeO3 on the redox reactions is proposed.