Improvement and mechanism for the fast response of a Pt/TiO2 gas sensor

Platinum is widely used in improving the response properties of gas sensors. This work aims to promote the rate of response of a Pt/TiO2 sensor exposed to H2/O2. The surface of the sensing layer was modified by an H2PtCl6-containing solution and treated under different conditions. The sensor treated at 900 °C showed a response time of about 40 millisecond (ms) when exposed to H2 and 20 ms exposed to O2 at 500–800 °C. Results indicate that the response time, which reflects the rate of change of the sensor resistance, was controlled by the activation energy (E). Sensors with lower activation energy exhibited a faster rate of response when the magnitude of response was approximately uniform. The response properties, on the other hand, were promoted by increasing the amount of platinum particles dispersed on the sensor surface via a spill-over effect.