A Temperature-Modulated Gas Sensor Based on CdO-Decorated Porous ZnO Nanobelts for the Recognizable Detection of Ethanol, Propanol, and Isopropanol

Although the relative response of metal oxide chemiresistive gas sensors has been greatly improved by using their nanostructures as sensing units, it remains challenging to recognize the detected gases due to their intrinsic cross-sensing properties. Here, by considering the temperature dependence of the sensing activity for metal oxide gas sensors, the dynamic sensing behavior of CdO (9 at%)-decorated porous ZnO nanobelts as an example was systematically investigated under a continuously changing working temperature. This working temperature modulation was achieved by precisely manipulating high and low heating voltages with a rectangular wave mode. In some working temperature ranges, the fabricated gas sensor exhibited characteristic response curves toward propanol, isopropanol, and ethanol, which were discriminated from other investigated volatile organic compounds (VOCs). Under periodical working temperature modulation, their characteristic response curves were repeatable and stable. In addition, the relationships between the relative responses at characteristic sensing temperature points and their concentrations were investigated. This work offers a promising strategy for using sensing nanomaterials for the highly sensitive recognition and analysis of VOCs, while avoiding cross-sensing.