A low temperature operating gas sensor with high response to NO2 based on ordered mesoporous Ni-doped In2O3

Abstract

The ordered mesoporous Ni-doped In₂O₃ and undoped In₂O₃ nanostructures have been synthesized via a nanocasting method, which is an easy, repeatable and friendly route. The structure of the as-prepared product was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen physisorption and scanning electron microscopy (SEM). The results of XRD and TEM revealed the ordered structure of undoped and Ni-doped In₂O₃. The wide-angle XRD of the samples revealed that Ni incorporation may lead to lattice deformation without destroying the original crystal structure. Gas sensors based on undoped and Ni-doped In₂O₃ were fabricated and their gas sensing properties were tested. The Ni-doped In₂O₃ based sensor showed excellent selectivity toward NO₂ at the operating temperature of 58 °C and the detection limit was 10 ppb. The response of the sensor based on mesoporous Ni-doped In₂O₃ was nearly 4 times higher than that of the sensor based on mesoporous undoped In₂O₃.