Enhanced NO2 gas sensing properties by Ag-doped hollow urchin-like In2O3 hierarchical nanostructures

Abstract

Ag-doped hollow urchin-like spheres In2O3 hierarchical nanostructures are developed for NO2 detection. Such unique architectures are synthesized by a facile and efficient solvothermal route combined with the subsequent thermal treatment. Various techniques, including X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) were employed to acquire the crystalline and morphological information of the as-obtained samples. Gas sensing performances of the sensor devices fabricated from pure and Ag-doped In2O3 were systematically investigated. The results indicate that the sensors based on Ag-doped In2O3 in certain molar ratio of AgNO3 to In2O3 (1:100) exhibit the largest response toward 1ppm NO2, which is almost 23 times higher than that of the sensor based on pure In2O3 at the optimum operating temperature. It demonstrates that the Ag-doping can significantly improve the response to NO2. The excellent and enhanced NO2 sensing performances of Ag-doped In2O3 can be attributed to its novel hierarchical structure and the catalytic activity of Ag nanoparticles.