Special nanostructure control of ethanol sensing characteristics based on Au@In2O3 sensor with good selectivity and rapid response

Abstract

A unique Au@In₂O₃ core–shell nanostructure was firstly prepared through a simple sol–gel method, the structure and morphology were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The results showed that unique architectures were core–shell nanostructure assembled from an Au core and an In₂O₃ shell. The gas sensing properties of the as-prepared pure In₂O₃ and Au@In₂O₃ core–shell samples were tested toward various gases. The sensor based on a Au@In₂O₃ core–shell nanostructure showed excellent selectivity toward ethanol at the operating temperature of 160 °C, giving a response of about 36.14 to 100 ppm, which was about 1.5 times higher than that of the sensor based on pure In₂O₃. The τ_res and the τ_rec values of the Au@In₂O₃ sensor to 100 ppm ethanol were 4 s and 2 s respectively, while those of the pure In₂O₃ sensor were relatively long. The enhancement might be attributed to the unique core–shell structure and existence of a Schottky junction between Au/In₂O₃.