Rapid Detection 2-Butanone Gas Sensors Based on Biphase In₂O₃ Nanocubes Modified With Ag NPs and SnO₂ QDs at Low Working Temperature

Increasing attention has been paid to environmental protection and human health. The 2-butanone is widely applied in industrial and pharmaceutical production causing small-area high-concentration harmful gas and large-area air pollution. The importance of quick and accurate detection is self-evident. In this work, the butanone-sensitive biphase In2O3 nanocubes codecorated with SnO2 quantum dots (QDs) and Ag nanoparticles (NPs) were prepared through a two-step hydrothermal strategy. Meanwhile, a fantastic detection speed and ultrahigh selectivity at lower operating temperatures were experimentally determined. The test results show that the 1 mol% SnO2 QDs and 3 mol% Ag NPs codecorated In2O3-based sensor have an ultrafast response speed (4.6 s) and a better response value $(119)$ at the low working temperature ( $160~^{\circ }$ C) to 50-ppm 2-butanone gas. Compared to the previous work, it has significantly improved the cross-selectivity with acetone. With rh-In2O3 being highly defective crystal surfaces and abundant oxygen vacancies, the biphase homojunction plays a key role in decreasing working temperature, for electron flow between two crystalline phase interfaces. The electronic sensitization effect of the Ag element and the quantum effect of SnO2 QDs accelerate the detection speed. Moreover, the heterojunction between rh-In2 O3 and SnO2 and the Schottky junction between Ag NPs and c-In2O3 largely improve the response capability. The significance of this study is not only to provide a sensor that can accurately detect butanone gas in industrial production and air pollution but also to provide new design ideas for preparing rapid detection semiconductor gas sensors at low working temperatures. The sensor performance in this study indicates that this sensor design scheme can enhance the accuracy and detection speed of butanone sensors used in exhaust gas detection.