Various ratios of TiO2-WO3 and Au/TiO2-WO3 composites were prepared as ozone-sensing materials. These materials were characterized by temperature-programmed reduction, UV-visible reflective spectra, transmission electron microscopy, and X-ray diffraction. A 460-nm blue LED light source was used for the detection of gaseous ozone, and the sensing properties of various ratios of TiO2-WO3 were measured. Among the various weight ratios of TiO2-WO3, the sensor response of the TiO2-WO3 (3:1) was the highest obtained response (23.8) to 2.5 ppm ozone. By adding 0.1 wt.% Au to the TiO2-WO3 (3:1), the sensor response was improved to 64.0. The ozone-sensing properties are attributed to the mechanism of adsorption, photoreduction, desorption, and the surface reaction processes of ozone. (C) 2014 Elsevier B.V. All rights reserved.