Research Article Size-DependentChlorinatedNitrogen-DopedCarbonNanotubes: Their Use as Electrochemical Detectors for Catechol and Resorcinol Winny Kgabo Maboya 1 andMologadiNkiyasiRantho 2 1 Department of Biotechnology and Chemistry, Faculty of Applied and Computer Sciences, Vaal University of Technology, Private Bag X021, Vanderbijlpark 1900, South Africa 2 Department of Physics, Mathematics and Non-Destructive Testing, Faculty of Applied and Computer Sciences, Vaal University of Technology, Private Bag X021, Vanderbijlpark 1900, South Africa Correspondence should be addressed to Winny Kgabo Maboya; winnyma@vut.ac.za Received 3 May 2023; Revised 1 July 2023; Accepted 14 July 2023; Published 24 July 2023 Academic Editor: Hamish Andrew Miller Copyright © 2023 Winny Kgabo Maboya and Mologadi Nkiyasi Rantho. Tis is an open access article distributed under the CreativeCommonsAttributionLicense,whichpermitsunrestricteduse,distribution,andreproductioninanymedium,provided the original work is properly cited. In this study, various-sized nitrogen-doped carbon nanotubes (NCNTs) were fabricated by varying the concentration of chlorine inthefeed.TediameteroftheNCNTswasfoundtoinfuence the sensing ability of the nanomaterials when coated onto the glassy carbonelectrode(GCE)andusedforthedetectionofcatechol(CC)andresorcinol(RS).LargerdiameterNCNTs(denotedNCNTs (2 :1)) were produced when a low concentration of chlorine was added into the acetonitrile feed, whereas smaller diameter NCNTs (denoted NCNTs (1: 2)) were produced when a large concentration of chlorine was added. Tis investigation revealed that the addition of controllable amounts of chlorine during the fabrication of NCNTs led to the creation of nanostructures with diferent properties. Te greatest current response which was evidenced by an enhanced anodic peak of CC and RS was obtained when GCE was coated with NCNTs (2 :1), and this was attributed to their large diameter and high graphitic nature which facilitated electron transfer as evidenced by scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analysis. A linear response was obtained when varying the concentration of both CC and RS, with the limits of detection of about 0.059 μM (CC) and 0.034 μM (RS) (3S/M) obtained. 1.Introduction Phenol and its derivatives are widely used in many felds, such as tanning, cosmetic, dye, chemical, and pharmaceu- tical industries [1, 2]. Tese compounds contain aromatic rings with one or more hydroxyl groups functionalized on the carbon atom, ranging from simple phenols to high molecular weight polymers. Terefore, the development of methods that can be used for sensitive and selective mon- itoring of phenolic compounds is very important for en- vironmental protection [3, 4]. Catechol (CC) and resorcinol (RS), together with hydroquinone (HQ), are a class of phenolic compounds called dihydroxybenzene isomers and are extensively used as chemical intermediates in the manufacture of many products, such as pesticides, agrochemicals, dyes, cosmetics, food additives, medicines, insecticides, and explosives [5–7]. Tese phenolic com- pounds are known as one of the signifcant threats for environmental pollutants because of their poor degradability and strong toxicity in nature [8, 9]. Traces of CC and RS are widely distributed in our ecosystem, for example, in our water sources, and they usually coexist as pollutants [10–12]. It is known that CC can produce renal tube destruction, liver function reduction, and strong central nervous system suppression when adsorbed in the gastrointestinal tract at high doses [13]. On the other hand, prolonged exposure to RS resulted in suppression of thyroid hormone synthesis in humans, haematological abnormalities, carcinogenesis, and fatal cases of human fetus poisoning [14]. As such, catechol is considered more toxic than resorcinol, and both are Hindawi International Journal of Electrochemistry Volume 2023, Article ID 7977453, 17 pages https://doi.org/10.1155/2023/7977453