The catalytic effect of SmInO3 on the gas-sensing properties of CdIn2O4

The catalytic effect of SmInO3, on the conduction and gas-sensing properties of CdIn2O4 was investigated. The results demonstrated that SmInO3 increases the electrical impedance and improves the sensitivity and selectivity of CdIn2O4 materials to ethanol gas though SmInO3 based sensors exhibit no sensitivity to reducing gases. The XPS analysis shows that the increase in sensitivity is not related to the increase in the amount of adsorbed oxygen O−(ad) on the material surface. We attribute the sensitivity improvement to the easy adsorption of reducing gas on the surface of SmInO3 and CdIn2O4 composite and the interfaces between the CdIn2O4 grains and the SmInO3 grains. The sensors based on CdIn2O4 and SmInO3, (molar ratio 3:2) have a high sensitivity and selectivity to ethanol gas and are promising for practical use.