Cobalt Oxide Nanorod-Modified GCE as Sensitive Electrodes for Simultaneous Detection of Hydroquinone and Catechol

Abstract

An electrochemical sensor based on a cobalt oxide nanorod (Co3O4NR) modified glassy carbon electrode (GCE) (Co3O4NR-GCE) was prepared for simultaneous and selective determination of hydroquinone (HQ) and catechol (CT). Surface morphology and crystallinity of Co3O4NR were investigated employing field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analysis. The structure (16 nm) of the Co3O4 nanorod was observed in the FESEM image. A sharp peak pattern in the XRD survey revealed the following crystal planes in Co3O4NR material: (111), (220), (311), (222), (400), (422), (511), and (440). Electrochemical characterization of modified Co3O4NR-GCE was carried out performing cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Selective and simultaneous detection of HQ and CT was carried out by performing CV and differential pulse voltammetry (DPV) analysis. In both studies, modified Co3O4NR-GCE showed well defined oxidation and reduction peaks for HQ and CT with enhanced peak current, and the oxidation peaks for HQ and CT were observed at 0.152 V and 0.254 V, respectively, in the CV analysis. Scan rate and pH variation analysis were performed to evaluate different kinetic parameters, including charge transfer coefficient (α = 0.56 for HQ and 0.66 for CT), heterogeneous charge transfer rate constant (ks = 56 for HQ and 72 for CT), and the number of electrons involved in HQ and CT oxidation. Quantitative analysis of HQ and CT was studied by observing the current response of DPV analysis with respect to concentration variation. Here, the detection limit was calculated as 0.2 µM for HQ with a linear concentration range of 5–200 µM, and 0.4 µM for CT with a linear concentration range of 5–150 µM. The practical applicability of the proposed sensor was investigated using sample solutions prepared in tap water. The reported sensor showed impressive selectivity towards HQ and CT in the presence of common interferents.

Fe(II)-Based Metallo-Supramolecular Polymer Film for Electrochemical Detection of Nitrite: Studies of Kinetics and Reaction Mechanisms

“…These results indicate that the oxidation process is controlled by diffusion. 46 The regression equation (E pa = 0.78 + 0.063 logv) and regression coefficient (R 2 = 0.99) obtained from the analysis of peak potential (E p ) vs logarithm of scan rate (log v), as shown in Fig. 5c, revealed that the oxidation process was irreversible.…”

Recent advances in hydrothermally and solvothermally grown Co3O4 nanostructures for electrochemical energy storage (EES) applications: a brief review

“…In 1960, cobalt oxide was studied for the first time as a catalyst for the total oxidation of hydrocarbons and carbon monoxide. 60 It was then studied for various applications, such as an active material in electrochromic devices (as it switches from intense brown in the oxidized state (colored state) to green in the reduced state (bleached state)), 27,61 solid-state gas sensors, 62 active and stable heterogeneous catalysts, 63 magnetoresistive devices, 64 as a negative electrode in rechargeable lithium batteries, 42 in water splitting, [65][66][67] as a sensor for determination of nitrite in wastewater, 68,69 acetaminophen detection in biological samples and commercial pharmaceutical preparations, 70 electrode material for the vanadium flow battery (VFB), 71 photoelectrochemical applications (PEC), 72 in the development of latent fingerprints, 73 to detect hydrogen peroxide in the nanomolar concentration range, 74 environmental remediation applications, such as the degradation of dyes, dye waste, and antibiotics, sodium-ion hybrid capacitors (SICs), 75 in diverse catalytic and biomedical applications due to its unique antimicrobial, anticancer, catalytic, antioxidant, antifungal, and enzyme inhibition properties, 76,77 an electrochemical sensor for simultaneous and selective determination of hydroquinone (HQ) and catechol (CT), 78 field effect transistors, 79 solar cells, 80 as a photocatalyst, 81 for anticancer treatment applications 82 and so on. Applications of Co 3 O 4 in various fields are listed in Fig.…”

Synchronized electrochemical detection of hydroquinone and catechol in real water samples using a Co@SnO2–polyaniline composite

“…1 Ecosystems have a high level of toxicity of these chemicals. 2 Catechol and its isomers are included as a category of hazardous water contaminants in both the EPA and EU databases. [3][4][5] Due to the similarities in their chemical structures and properties, simultaneous detection of Hq and Cat is difficult.…”