Single Bimodular Sensor for Differentiated Detection of Multiple Oxidative Gases

Abstract

Semiconductive metal-oxide sensors suffer from cross-sensitivities under mixed chemical condition, specifically upon mixture of multiple oxidative or reducive gases. Herein, a single bimodular sensor has been demonstrated for smart differentation of multiple oxidative analytes by relating the resistance-metric mode to impedance-metric mode. The sensor construct based on ZnO nanorods readily outputs three response datasets upon exposure of oxidative-gas mixture including O 2 , SO 2 , and NO 2 , the resistance, real part impedance, and imaginary part impedance. The differentiative and correlated nature between these response signals allows such a single sensor platform to differentiate these oxidative gases accurately and robustly. Linear and non-linear decision boundaries were established over a large gas-concentration range from 2 ppm to 3 % through a combination of principal component analysis and artificial neural network training. A facile user interface was demonstrated for recognition and measurement of unknown gas analytes, with the error of the predicted analyteconcentration as low as 2 %.

Intelligent Gas Detection: g-C3N4/Polypyrrole Decorated Alginate Paper as Smart Selective NH3/NO2 Sensors at Room Temperature

“…As a dimensionality reduction technique for machine learning (ML), principal component analysis (PCA) transforms high-dimensional data into a lower-dimensional representation, reducing the impact of errors, and improving recognition accuracy. After applying PCA, the data can be projected onto a 2D plane. , In Figure S7, the total variance explained by PC1 (65%) and PC2 (20%) is approximately 85%. Moreover, the key features selected during the dimensionality reduction process still retain a significant amount of the original information, facilitating a better understanding and interpretation of the data.…”

“…After applying PCA, the data can be projected onto a 2D plane. 45,46 In Figure S7, the total variance explained by PC1 (65%) and PC2 (20%) is approximately 85%. Moreover, the key features selected during the dimensionality reduction process still retain a significant amount of the original information, facilitating a better understanding and interpretation of the data.…”

Metal Oxide-Based Sensors for Ecological Monitoring: Progress and Perspectives

“…In [203], Burgués et al utilized similar algorithms, a quadcopter, and two commercial SMO sensors to detect ethanol vapor sources in closed rooms and created a 3D map of gas concentration with a special resolution of 1.38 m. Notably, the measurements were conducted during continuous "sweeps" across the rooms, demonstrating the ability of the proposed algorithm to be utilized effectively and interpret data from relatively slow SMO sensors. The authors of [110] demonstrated the ability to effectively detect and distinguish between three different gases (O 2 , SO 2 , and NO 2 ) in a mixture with a single ZnO-based sensor. To achieve this functionality with an error of under 2%, resistance and impedance measurements were used, followed by data processing by an artificial neural network.…”

Low-Concentration NOx Gas Analysis Using Single Bimodular ZnO Nanorod Sensor

“…18 To tackle these challenges, we demonstrated a single multimode sensor strategy in our previous work to enable direct measurement of the gas analyte mixture. 19 Such a multimodal sensor may integrate the merits of the traditional sensor array and single-mode sensor, where multifacet sensing signals in resistance and impedance response could be provided to evaluate the mixture on the basis of a simplified electrical feedthrough. It is noted that traditional sensor arrays integrate multiple devices or utilize massive data processing techniques 20 to achieve simultaneous recognition of different analytes and precise quantification.…”

“…To tackle these challenges, we demonstrated a single multimode sensor strategy in our previous work to enable direct measurement of the gas analyte mixture . Such a multimodal sensor may integrate the merits of the traditional sensor array and single-mode sensor, where multifacet sensing signals in resistance and impedance response could be provided to evaluate the mixture on the basis of a simplified electrical feedthrough.…”