A Highly Selective and Fast-Responding Hydrogen Sensor based on In2O3 Nanocubes

The In2O3 nanocubes were successfully synthesized without any templates by calcining the In (OH) 3 precursor in air at 300 oC for 2 h and their H2 sensing characteristics were investigated. The In (OH) 3 precursor was prepared through a wet chemical route at room temperature (27 oC) using InCl3, 4H2O and NH4OH as starting materials. The formation of In2O3 nanocubes was confirmed by X-ray diffraction measurement (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis. The In2O3 nanocubes exhibit excellent H2 sensing properties such as, high gas response (~ 130 to 50 ppm H2 at 325 oC), extremely rapid response (1 s), fast recovery (4-5 s), excellent repeatability and good selectivity. Furthermore, the lower detection limit is ~3.87 ppm, which is lower than the permissible explosive limit for H2. The experimental results demonstrate the potential of the In2O3 nanocubes as sensing material in the fabrication of hydrogen sensors.