Sensing performance of Au-decorated In2O3 microcubes to ppb-level NO2: Experimental and DFT investigations

Highly selective and sensitive detection to toxic and hazardous gases with low concentrations is important, but difficult to detect ppb-level NO2 or slow response & recovery hinders the practical applications of the In2O3-based composites in the detection of NO2 to a great extent. In this work, we synthesized the pristine In2O3 and Au-decorated In2O3 (Au-In2O3) microcubes by hydrothermal method using F-127 as a template agent. The experimental results reveal that the Au-In2O3-0.5 sample exhibits the best /Auresponse of 26.5 to NO2 of 2 ppm at the optimum test temperature of 200 degrees C, with respective response and recovery time of 50 and 52 s. Moreover, the lowest detection concentration (LDC) arrives at 10 ppb. In particular, the low concentrations of NO2 can be detected at room temperature. Moreover, the Au-In2O3 sample presents excellent linear response (R-2 =0.99015), selectivity, reproducibility, and stability to NO2. The improvement mechanism of gas sensitivity is also briefly discussed, which can be mainly ascribed to the spillover effect from Au nanoparticles and the surface reaction. This research provides a promising candidate gas sensing material sensitive to NO2 with low concentration.

Automated summary

This study successfully achieved highly selective and sensitive detection of low concentrations of NO2 using Au-In2O3 composite material, with fast response and recovery time, and the ability to detect low concentrations of NO2 at room temperature.