Highly sensitive and low detection limit NO2 gas sensor based on In2O3 nanoparticles modified peach kernel-like GaN composites

The effective detection of ppb-level NO2 is of great significance to the natural environment and human health. In this work, a series of In2O3 nanoparticles modified peach kernel-like GaN for NO2 detection was synthesized by a concise two-step method. The gas-sensing results showed that 10 mol% In2O3-decorated GaN (In: Ga) exhibited a response as high as 1070.9–1 ppm NO2 at the working temperature of 100 ℃, as well as a low limit of detection (1 ppb). Furthermore, the sensor also possessed excellent selectivity, repeatability and fast response-recovery speed. The outstanding sensing performance was contributed to the rough and porous microstructure of GaN, abundant negative oxygen ion species originating from In2O3, and the heterojunction effect between GaN and In2O3. The sensor proposed herein provide a useful reference for reliable detection of ppb-level NO2 gas. •In2O3 nanoparticles modified peach kernel-like GaN was synthesized by a concise two-step method.•In2O3 nanoparticles greatly increased the adsorbed oxygen species on the surface of GaN.•The response of GaN/In2O3 composites can reach 1070.9–1 ppm NO2, and the limit of detection is 1 ppb.