Au/ZnO/In₂O₃ nanoparticles for enhanced isopropanol gas sensing performance

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.