ABSTRACT
In this paper, a series of Au/ZnO/In2O3 nanoparticles are synthesized by a facile one-step hydrothermal method. The gas sensing properties of Au/ZnO/In2O3 materials are investigated in detail. The response of 2%Au/1%ZnO/In2O3 material to isopropanol increases to six times that of pure In2O3 materials. In contrast to a pure In2O3 sensor, the optimal working temperature of the 2%Au/1%ZnO/In2O3 sensor decreases to 40 °C. The sensing mechanism of Au/ZnO/In2O3 nanoparticles is mainly explained through the influence of the n-n heterojunction formed by In2O3 and ZnO. In addition, the introduction of Au contributes to an increase in the gas response. A possible reason is that the introduction of Au produces smaller sized particles on the sensor surface, creating a larger surface area, enhancing the response.
ABSTRACT
We prepared ZrO2-ZnO heterojunction composites by a simple hydrothermal method as materials sensitive to isopropanol gas. The 5% ZrO2-ZnO sample presented a uniform rod-like structure. The optimum operating temperature, sensitivity and response/recovery times were measured to investigate the response of ZrO2-ZnO composites to isopropanol. The sensor based on 5% ZrO2-ZnO composites at an optimum temperature of 260 °C had a response to 100 ppm isopropanol of up to 172.46, which was about 3.6 times higher than that of pure ZnO. The sensor also exhibited fast response and recovery times of 5 s and 11 s, respectively. The gas-sensitive properties can be attributed to the rod-like structure, heterojunction structure and catalytic activity of ZrO2. These results would contribute in expanding the application of ZrO2 in gas sensors.
