Designed synthesis of Co-doped sponge-like In2O3 for highly sensitive detection of acetone gas

Pure and 1–4 mol% cobalt doped indium oxide (Co-doped In2O3) sponge-like microstructures with high specific surface area were fabricated by a simple and environmentally friendly hydrothermal method. The specific surface area and porosity of Co-doped sponge-like In2O3 microstructures can be regulated through the modulation of Co/In molar ratios. The as-prepared sensors based on Co-doped In2O3 exhibit favorable gas sensing properties toward acetone gas; their porous structure can create more adsorption sites for the adsorption of oxygen molecules and the diffusion of the target gas, leading to significant improvement in sensing performance. In particular, 3 mol% Co-doped In2O3 presents the greatest response to acetone vapor at 240 °C, which is about 3.25 times higher than that of pure In2O3. The sensor also exhibits rapid response-recovery time (1.143 s/37.5 s), low detection limit (2.76 at 5 ppm), good reproducibility and high selectivity, making it a promising material for acetone detection.