Expanding Selectivity Functionality of a ZnO Nanotetrapod-Based Volatile Organic Compound Sensor Using Au Nanoparticle Decoration

Abstract

Gas sensors with multiselectivity are drawing increasing attention and sensors with temperature-tuned dual selectivity have been developed. Because Au nanoparticles (NPs) can lower the activation barrier for sensing reactions, herein, Au NP decoration was used to expand the selectivity range of a ZnO nanotetrapod (NTP)-based sensor. A temperature-tuned triselectivity sensor based on Au NP–ZnO NTPs was developed. The sensor exhibited enhanced selectivity for formaldehyde when the operation temperature was <200 °C, ethanol when the operation temperature was between 200 and 340 °C, and acetone when the operation temperature was >400 °C. Additionally, Au NP decoration increased the magnitude of response and decreased the optimal detection temperature of the sensor. This work demonstrates that Au NP decoration is an efficient approach for improving the performance of semiconductor-based gas sensors with temperature-tunable selectivity.