The surface tailored metal oxide nanostructures for the development of non-enzymatic sensors are highly demanded, but it is a big task due to the wide range of complexities during the growth process. The presented study focused on the surface modification of the heterogeneous morphology of cobalt oxide (Co3O4) prepared by the hydrothermal method. Further surface modification was conducted with the use of sodium citrate as a reducing and surface modifying agent for the Co3O4 nanostructures through the high density of oxygenated terminal groups from the citrate ions. The citrate ions enabled a significant surface modification of the Co3O4 nanostructures, which further improved the electrochemical properties of the Co3O4 material toward the design of the non-enzymatic ascorbic acid sensor in a phosphate buffer solution of pH 7.4. The morphology and crystal arrays of the Co3O4 nanostructures were studied by scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) techniques. These physical characterizations showed the highly tailored surface features of Co3O4 nanostructures and a significant impact on the crystal properties. The electrochemical activity of Co3O4 was studied by chronoamperometry, linear sweep voltammetry, and cyclic voltammetry (CV) for the detection of ascorbic acid. The linear range of the proposed sensor was measured from 0.5 mM to 6.5 mM and a low limit of detection of 0.001 mM was also estimated. The presented Co3O4 nanostructures exhibited significant surface roughness and surface area, consequently playing a vital role toward the selective, sensitive, and stable detection of ascorbic acid. The use of a low cost surface modifying agent such as sodium citrate could be of great interest for the surface roughness and high surface area of nanostructured materials for the improved electrochemical properties for the biomedical, energy storage, and conversion systems.
The fabrication of enzyme‐free glucose sensors is highly demanded for the biological, clinical, and food applications. In this study, we have developed a green method for tuning the surface properties of nickel‐cobalt bimetallic oxide (NiCo2O4) by adding mustard (Brassica Campestris) leaves extract during hydrothermal growth. The mustard (Brassica Campestris) leaves extract is rich with a variety of phytochemicals, which can easily tune the surface properties of NiCo2O4 nanostructures, thereby paving the way toward the development of sensitive and selective non‐enzymatic glucose sensors. The effect of various amounts of mustard (Brassica Campestris) leaves extract (0–20 ml) was also studied to find out the optimal conditions for growing surface‐modified NiCo2O4 nanostructures. The morphology and crystalline structure of the nanomaterials were studied by scanning electron microscopy (SEM) and powder X‐ray diffraction (XRD) techniques, respectively. The presence of an increasing quantity of mustard (Brassica Campestris) extract keeps the crystalline structure and the morphology of the NiCo2O4 nanostructures unaltered but changes their dimensions. All nanostructures show the same cubic spinel structure of NiCo2O4 and a morphology of spherical urchins composed of nanorods, but the diameter of the urchins decreases from ~10 μm to several nanometers, thus increasing the surface area of the nanomaterial. Furthermore, NiCo2O4 nanostructures were deposited onto glassy carbon electrodes (CGE), showing excellent catalytic properties toward the enzyme‐free detection of glucose using cyclic voltammetry. Importantly, the intensity of the oxidation current peak was linear over a wide range of glucose concentrations (from 0.1 to 10 mM) and the limit of detection (LOD) was estimated around 0.001 mM. Additionally, NiCo2O4 nanostructures grown in the presence of 20 ml of mustard leaf extract demonstrated good repeatability and excellent selectivity for glucose, without interference by other components such as urea, lactic acid, uric acid, ascorbic acid, as well as potassium and sodium ions. The combined results attest that mustard leaf extract has high potential as a green approach to improve the electrochemical properties of nanostructured materials, and could be useful for a wide range of materials for future electrochemical applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.