Facile synthesis of In2O3 nanoparticles with high response to formaldehyde at low temperature

In₂O₃ nanoparticles with uniform particle size (10-25 nm) were obtained using the facile precipitation strategy at room temperature with following calcined treatment. The gas-sensing performance of In₂O₃ nanoparticles with different calcined temperatures was investigated. The results demonstrated that the In₂O₃ nanoparticles calcined at 500°C exhibited highest sensing response (R_a/R_g = 68.1) to 10 ppm HCHO at 100°C with good selectivity, stability, reproducibility, and ultra-low limit of detection (1 ppm). The results of XPS, UV, and other characterizations indicated that In₂O₃-500 possessed the most absorbed oxygen species, the highest carrier mobility, and lowest band gap energies. Our work offers new insights into the development of sensing materials to the detection of volatile organic compounds (VOCs).