Rapid detection of trace ozone in TiO2-In2O3 materials by using the differential method

TiO2-In2O3 composites were fabricated for detecting trace amounts of gaseous ozone and were characterized using transmission electron microscopy, X-ray diffraction, and ultraviolet-visible spectrophotometry. The fabricated TiO2-In2O3 composites exhibited a high ozone gas sensor response of 56.5-2.0 ppm at room temperature (25 ± 2 °C) under irradiation at 405 nm using a light-emitting diode. The differential function dR/dt (R, sensor resistance; t, time) was used to analyze ozone concentrations from 40 to 2000 ppb, and a favorable regression coefficient of R2 = 0.997 was obtained. In addition, the results revealed that the ozone sensor exhibited a rapid response rate of 30 s and favorable short-term stability to 2.0 ppm ozone. A possible sensing mechanism was proposed.