Electrostatic deposition and functionalization of CVD grown multiwalled carbon nanotubes for sensitive & selective detection of CO and NOx at room temperature

• Published in: Analytica chimica acta 2021-09, Vol.1177, p.338766, Article 338766
• Main Authors: Shukla, Prashant, Saxena, Pooja, Bhatia, Vasuda, Jain, V.K.
• Format: Article
• Language: English
• Subjects: Chemiresistive; Gas sensor; Humans; MWCNTs; Nanotubes, Carbon; Nitrogen Oxides; NOx; Static Electricity; Temperature
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2021.338766

Among the most toxic and suffocating gases in industries and mines are carbon monoxide (CO) and nitrogen oxides (NOx). The electrostatically functionalized self-assembled MWCNT (f-MWCNTs) were employed to develop a sensing device to selectively sense gases such as CO and NOx with high sensitivity and repeatability to as low as sub-ppm levels. The resistive gas sensor's operation is primarily based on changes in the electrical resistance of the f-MWCNT network as a result of its selective interaction with the specific target gas in a two-pole format. The degree to which the electrical resistance of the sensing film increases or decreases is determined by the concentration of the target gas to which it is exposed. As a result, the target gas can be detected both qualitatively and quantitatively. The sensitivity of 100 ppb and 300 ppb with the sensor response time of ∼30 s and ∼50 s for NOx and CO respectively were recorded using our gas sensor and was found noticeably efficient than conventional MOS-based solid-state gas detectors. It was also realized that the corona-assisted, electrostatic, self-assembled MWCNT based sensor fabrication technique is fast, simple, low-cost, and environmentally friendly for commercial-scale production of gas sensors. This approach also extends many technical merits such as simultaneous deposition and functionalization of MWCNTs at (RT = 30 °C) room temperature for specific target analyte detection. These unique characteristics make f-MWCNTs based devices very appealing for real-time commercial and domestic gas sensing applications. [Display omitted] •Electrostatically functionalized self-assembled MWCNT (f-MWCNTs) synthesized via CVD technique.•Self-assembled network of f-MWCNT exhibited appreciably high sensitivity and selectivity to toxic gases.•Principal of operation depends on the variation in the electrical resistance of the f-MWCNT network on its exposure to the target gases.•NOx and CO with sensitivity, sensor response time and sensor response of 100 ppb and 300 ppb, ∼30 s and ∼50 s and 15% and 55% respectively were recorded.•A competent CO-NOx sensor which can sense and compute their leakage with prolonged high constancy and reproducibility.