# In2O3 Cauliflower Modified with Au Nanoparticles for O3 Gas Detection at Room Temperature

## TL;DR

This study develops a room-temperature ozone sensor using gold-modified indium oxide, showing significantly improved sensitivity and faster response times.

## Contribution

The novel Au-In2O3 nanocomposite enables high-performance ozone sensing at room temperature through synergistic effects of Au nanoparticles.

## Key findings

- Au-In2O3 sensor showed a 1398.4 response to 1 ppm O3 at room temperature, much higher than pristine In2O3.
- Response and recovery times were reduced to 102 and 358 seconds, respectively, with 1.0 wt% Au modification.
- Improved performance is attributed to the spillover effect and Schottky junction formation at the Au-In2O3 interface.

## Abstract

Metal oxide semiconductor (MOS)-based chemiresistive gas sensors, attributable to their low cost, compact structure, and long operational lifetime, have been widely employed for the detection and monitoring of trace ozone (O3) in environmental air. Moreover, as ozone is a highly reactive oxidizing species extensively used in medical device sterilization, hospital disinfection, and food processing and preservation, accurate monitoring of ozone concentration is also essential in medical sanitation and food safety inspection. However, their practical applications are often limited by insufficient sensitivity and the requirement for elevated operating temperatures. In this study, Au-modified indium oxide (Au-In2O3) nanocomposite sensing materials were synthesized via a hydrothermal route followed by surface modification. Structural and morphological characterizations confirmed the uniform dispersion of Au nanoparticles on the In2O3 surface, which is expected to enhance the interaction between the sensor and target gas molecules. The resulting Au-In2O3 sensor exhibited excellent O3 sensing performance under room-temperature conditions. Compared with pristine In2O3, the Au-In2O3 sensor with 1.0 wt% Au modification demonstrated a remarkably enhanced response of 1398.4 toward 1 ppm O3 at room temperature. Moreover, the corresponding response/recovery times were shortened to 102/358 s for Au-In2O3. The outstanding O3 sensing performance can be attributed to the synergistic effects of Au nanoparticles, including the spillover effect and the formation of a Schottky junction at the Au-In2O3 interface. These results suggest that Au-modified In2O3 cauliflower represents a highly promising candidate material for high performance O3 sensing at low operating temperatures.