Selective Detection of NO and NO₂ with CNTs-Based Ionization Sensor Array

Hui Song; Kun Li; Chang Wang

doi:10.3390/mi9070354

Selective Detection of NO and NO₂ with CNTs-Based Ionization Sensor Array

Micromachines (Basel). 2018 Jul 16;9(7):354. doi: 10.3390/mi9070354.

Authors

Hui Song¹, Kun Li², Chang Wang³

Affiliations

¹ School of Software Engineering, Qufu Normal University, Qufu 273165, China. songh_0315@mail.qfnu.edu.cn.
² College of Engineering, Qufu Normal University, Rizhao 276825, China. lk_20160606@mail.qfnu.edu.cn.
³ Department of Microelectronics, School of Electronics and Information Engineering, Xi'an Jiaotong University, Xi'an 710049, China. wangc369@126.com.

Abstract

The accurate detection of NO_x is an important issue, because nitrogen oxides are not only environmental pollutants, but also harm to human health. An array composed of two carbon nanotubes (CNTs)-based ionization sensors with different separations is proposed for NO and NO₂ selective detection. The experimental results indicate that the CNTs-based ionization sensor has an intrinsic, monotonically decreasing response to NO or NO₂. The sensor with 80 µm separations and 100 µm separations exhibited the highest sensitivity of -0.11 nA/ppm to 300 ppm NO and -0.49 nA /ppm to 70 ppm NO₂, respectively. Although the effect of the NO₂ concentration on the NO response is much stronger than that of NO on NO₂, the array of these two sensors still exhibits the ability to simultaneously detect the concentrations of NO and NO₂ in a gas mixture without component separation.

Keywords: NOx; carbon nanotube (CNT); ionization sensor array; non-self-sustaining discharge; selectivity.