Promotion effect of gold on TiO2 for gaseous formaldehyde sensing

• Sensor response was very high as 42 for 20 ppm HCHO.
• Room working temperature of semiconductor type HCHO sensor.
• Au/TiO2 sensor is a promising candidate as a practical formaldehyde gas sensor.

We report the successful preparation of gold/titanium dioxide (Au/TiO2) powders prepared by a simple impregnation method. The structural and morphological characterization of the as-prepared Au/TiO2 powders were performed by X-ray diffraction (XRD), specific surface area measuring instrument and transmission electron microscopy (TEM). When exposed to 10 ppm gaseous formaldehyde, the sensor response of TiO2 was 6.1. The 1% Au/TiO2-based formaldehyde sensor demonstrated a favorable room-temperature response of 20.6. The sensor response increased rapidly from 2.1 to 42.0 with formaldehyde concentration increases from 1.0 to 20 ppm. The study includes an investigation into the Au/TiO2 sensing mechanism for formaldehyde.