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

Abstract

Quantitative measurement of the nitrogen oxide mixture (NO x , usually of NO and NO2) usually relies on sophisticated, space-consuming, and expensive spectroscopy techniques such as gas chromatography (GC), Fourier-transform infrared spectroscopy (FTIR), and chemi-luminescence detection (CLD). The direct and portable measurement solutions are lacking in this regard. In this work, by utilizing the bimodular sensing strategy, we successfully demonstrated the differential measurement of NO x with errors smaller than 8.3%, by correlating the sensor electrical and electrochemical responses. The effective detection is successfully displayed in the low-concentration ranges of 1–10 ppm for NO and 100 ppb–1 ppm for NO2, where weak competitive gas co-adsorption mitigated the cross-sensitivities compared to the higher-concentration range. Based on the electron occupation with negligible competitive adsorption, the accurate theoretic prediction of the mixture responses versus component concentration relieves the reliance on repeated calibration and empirical functions. With the miniaturized size and simplified electrical feedthrough, the single bimodular nanorod sensor provides a promising solution for direct and portable NO x analysis at low concentrations.

Two-Dimensional MoS2 for Resonant-Gravimetric Detection of Ppb-Level Formaldehyde

“…The proportion of S 6+ in 1T-MoS 2 is also larger than that in 2H-MoS 2 , which proves that a part of S 2– in 1T-MoS 2 has been oxidized to SO 4. − The deconvolution of XPS peaks of the 1T phase reveals the composition of the 1T phase in 1T-MoS 2 is about 70.4% . We also tested the BET surface area of the two materials and their nitrogen adsorption/desorption curves, which are shown in Figure d.…”

“…Various detection methods, including colorimetry spectrophotometry, gas chromatography, fluorescence, chemiresistive, gravimetric, optical, and electrochemical, have been developed to achieve effective monitoring of trace HCHO. Most of the testing methods suffer from drawbacks of complicated operation and expensive equipment . Although the electrochemical sensor has the advantages of economy and simplicity, the detection limit is usually at the μM level .…”

“…Most of the testing methods suffer from drawbacks of complicated operation and expensive equipment. 10 Although the electrochemical sensor has the advantages of economy and simplicity, the detection limit is usually at the μM level. 9 Additionally, the FET-type sensor has a low detection limit (ppb level), but the response/recovery speed of the sensor needs to be further improved.…”

Highly efficient metalloporphyrin-based nanosensors for NO detection

“…In this regard, various materials, such as black phosphorus, 13 ZnO nanorods, 14 halide Cs 2 PtI 6 perovskites, 15 etc. , have been used as NO sensors.…”

“…However, developing low-cost, eco-friendly, and high-performance NO sensors that operate at room temperature is a challenging-but, of course, rewarding-task. 1 In this regard, various materials, such as black phosphorus, 13 ZnO nanorods, 14 halide Cs 2 PtI 6 perovskites, 15 etc., have been used as NO sensors. Yet, such sensors are not applied because of their high operating temperature, synthesis cost, and biological risks.…”