Polyethyleneimine-Starch Functionalization of Single-Walled Carbon Nanotubes for Carbon Dioxide Sensing at Room Temperature.

Content Provider	Europe PMC
Author	Manzoor, Samrah Talib, Mohammad Arsenin, Aleksey V. Volkov, Valentyn S. Mishra, Prabhash
Copyright Year	2022
Abstract	There is an ever-growing interest in the detection ofcarbon dioxide(CO2) due to health risks associated with CO2 emissions. Hence, there is a need for low-power and low-cost CO2 sensors for efficient monitoring and sensing of CO2 analyte molecules in the environment. This study reports on thesynthesis of single-walled carbon nanotubes (SWCNTs) that are functionalizedusing polyethyleneimine and starch (PEI-starch) in order to fabricatea PEI-starch functionalized SWCNT sensor for reversible CO2 detection under ambient room conditions (T = 25°C; RH = 53%). Field-emission scanning electron microscopy, high-resolutiontransmission electron microscopy, Raman spectroscopy, and Fouriertransform infrared spectroscopy are used to analyze the physiochemicalproperties of the as-synthesized gas sensor. Due to the large specificsurface area of SWCNTs and the efficient CO2 capturingcapabilities of the amine-rich PEI layer, the sensor possesses a highCO2 adsorption capacity. When exposed to varying CO2 concentrations between 50 and 500 ppm, the sensor responseexhibits a linear relationship with an increase in analyte concentration,allowing it to operate reliably throughout a broad range of CO2 concentrations. The sensing mechanism of the PEI-starch-functionalizedSWCNT sensor is based on the reversible acid–base equilibriumchemical reactions between amino groups of PEI and adsorbed CO2 molecules, which produce carbamates and bicarbonates. Dueto the presence of hygroscopic starch that attracts more water moleculesto the surface of SWCNTs, the adsorption capacity of CO2 gas molecules is enhanced. After multiple cycles of analyte exposure,the sensor recovers to its initial resistance level via a UV-assistedrecovery approach. In addition, the sensor exhibits great stabilityand reliability in multiple analyte gas exposures as well as excellentselectivity to carbon dioxide over other interfering gases such ascarbon monoxide, oxygen, and ammonia, thereby showing the potentialto monitor CO2 levels in various infrastructure.
Journal	ACS Omega
Volume Number	8
PubMed Central reference number	PMC9835164
Issue Number	1
PubMed reference number	36643491
e-ISSN	24701343
DOI	10.1021/acsomega.2c06243
Language	English
Publisher	American Chemical Society
Publisher Date	2022-12-20
Access Restriction	Open
Rights License	Permits non-commercial access and re-use, provided that author attribution and integrity are maintained; but does not permit creation of adaptations or other derivative works (https://creativecommons.org/licenses/by-nc-nd/4.0/). © 2022 The Authors. Published by American Chemical Society
Content Type	Text
Resource Type	Article
Subject	Chemistry Chemical Engineering