Preparation of 2-Butanone Gas Sensor Based on Ag-Decorated In2O3 Nanocube with High Response and Low Detection Level

Abstract

In this work, 2-butanone-sensitive Ag-decorated In2O3 nanocomposites were successfully prepared using a facile one-step hydrothermal method to enhance the sensing performance of In2O3 nanocubes. The methods of scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) analysis, and X-ray photoelectron spectroscopy (XPS) were used to observe the morphology, microstructure, crystalline phase, and the existing state of the elements in the produced nanomaterials, respectively. The gas sensing test results show that the prepared compounds could respond to 100 ppm of 2-butanone with a high response (242), fourfold that of the pure In2O3 material, at the optimum working temperature of 240 °C. Moreover, the Ag@In2O3-based sensor also showed excellent selectivity, good repeatability, and even long-term stability. In addition, noble metal surface modification not only decreased the optimum operating temperature (from 270 °C to 240 °C) but also decreased the lowest detection limit (from 5 ppm to 0.25 ppm). In the final section, the gas sensing mechanism of the Ag@In2O3-based sensor and the probable reason for 2-butanone’s enhanced sensing properties are both discussed.