Rapid and Stable Detection of Carbon Monoxide in Changing Humidity Atmospheres Using Clustered In2O3/CuO Nanospheres

• Published in: ACS sensors Vol. 5; no. 4; pp. 1040 - 1049
• Main Authors: Sun, Yongjiao, Zhao, Zhenting, Suematsu, Koichi, Li, Pengwei, Yu, Zhichao, Zhang, Wendong, Hu, Jie, Shimanoe, Kengo
• Format: Journal Article
• Language: English
• Published: American Chemical Society 24.04.2020
• Subjects: clustered nanospheres; antihumidity; rapid detection; CO; In2O3/CuO
• ISSN: 2379-3694; 2379-3694
• DOI: 10.1021/acssensors.9b02557

Clustered indium oxide/copper oxide (In2O3/CuO) nanospheres with different CuO amounts were successfully synthesized as sensing materials for the carbon monoxide (CO) detection. Component and morphological characterizations were performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Sensing performance for CO of the clustered In2O3 and In2O3/CuO nanospheres were investigated under different temperatures and humidity conditions. The results show that the sensors based on 2 mol % In2O3/CuO (InCu2) exhibit about threefold improvement in response to CO compared to that of In2O3 with quick response and recovery time, wide linearity, and low detection limit at 200 °C under 25% relative humidity (RH). Moreover, it shows tiny resistance and response declines despite the wide range of humidity variation from 25 to 95% RH. Meanwhile, the mechanism of enhanced gas-sensing performances and antihumidity properties of InCu2 were systematically investigated. We speculated that most of the water-driven species are predominantly adsorbed by CuO due to its high affinity to the hydroxyl group, which suppresses the interaction between moisture and In2O3. InCu2 is a new and promising material to sense CO in a highly sensitive and fast manner with negligible interference from ambient humidity.