Humidity-Tolerant Chemiresistive Gas Sensors Based on Hydrophobic CeO₂/SnO₂ Heterostructure Films

Abstract

The accelerated evolution of the Internet of Things has brought new challenges to the gas sensors, which are required to work persistently under harsh conditions, like high humidity. However, currently, it is quite challenging to solve the hindrance of the trade-off between gas-sensing performance and anti-humidity ability of the chemiresistive gas sensors. Herein, hydrophobic inorganic CeO 2 /SnO 2 heterostructure films were prepared by depositing the CeO 2 layers with a thickness of a few nanometers onto the SnO 2 film via a magnetron sputtering method. The sensors based on the CeO 2 /SnO 2 heterostructure films demonstrated excellent gas-sensing performance toward trimethylamine (TEA) with high response, wide detection range (0.04− 500 ppm), low record detection limit (0.04 ppm), ideal reproducibility, and long-term stability, while concurrently possessing promising antihumidity ability. A portable, wireless TEA-sensing system containing the CeO 2 /SnO 2 sensor was constructed to realize the real-time monitoring of trace concentration of the volatiles released from a fish. This work provides a novel strategy to prepare advanced chemiresistive gas sensors for humidity-independent detection of harmful gases and vapors and will accelerate their commercialization process in the field of food safety and public health.

Construction of Flower-like PtOx@ZnO/In2O3 Hollow Microspheres for Ultrasensitive and Rapid Trace Detection of Isopropanol

“…Under the same humidity, the responses of all gas sensors first increase gradually to the maximum values and then fall off to smaller values by degrees with the increase of working temperature. It is associated with the adsorption–desorption kinetics of the isopropanol molecules . Generally, the diffusion rates of isopropanol molecules increase as the working temperature increases, resulting in more amount of isopropanol molecules adsorbed on the surface of the sensing materials.…”

“…5 In addition, Pt@ZnIn 2 has a higher percentage of O II , which can provide more oxygen adsorption sites associated with the high gas response. 33 Generally, the diffusion rates of isopropanol molecules increase as the working temperature increases, resulting in more amount of isopropanol molecules adsorbed on the surface of the sensing materials. However, when the working temperature is beyond a threshold (optimal working temperature), the desorption process of isopropanol molecules dominates, leading to the deterioration of the sensing reaction and the recession of the response value.…”

Triethylamine Gas Sensors Based on BiOBr Microflowers Decorated with ZnO Nanocrystals

“…Moreover, a large number of oxygen species are adsorbed at the interface of n–n heterojunctions. , In addition, when the BiOBr/ZnO sensor is exposed to TEA, TEA will react with oxygen anions and release electrons, which narrows the EDL and reduces the resistance value. In a word, compared with ZnO and BiOBr, the BiOBr/ZnO sensor presents a more significant resistance change during TEA sensing, resulting in a higher response …”

“…In a word, compared with ZnO and BiOBr, the BiOBr/ZnO sensor presents a more significant resistance change during TEA sensing, resulting in a higher response. 46 Finally, as investigated by EPR, oxygen vacancies play an important role in the TEA sensing performance. Hou et al also reported that oxygen vacancies can be of immense benefit to the gas-sensitive properties.…”

Metal–oxide–semiconductor resistive gas sensors for fish freshness detection

“…In practical applications, the changes in ambient humidity will have a greater impact on the performance stability (sensitivity and response/recovery speed) and freshness assessment accuracy of TEA gas sensors, especially for devices with lower operating temperatures. To solve such problems, Zhu et al prepared hydrophobic inorganic CeO 2 /SnO 2 heterostructure films gas sensors, demonstrating excellent gas-sensing properties to TEA with high response, wide detection range (0.04-500 ppm), low detection limit (0.04 ppm), and long-term stability, while possessing promising anti-humidity sensing ability (Zhu et al, 2022). Xiong et al synthesized two-dimensional ultrathin ZnO/Co 3 O 4 heterostructure nanomeshes by in situ growth technology (Xiong et al, 2021).…”