Multiwalled Carbon Nanotube/Fe-Doped ZnO-Based Sensors for Droplet Electrochemical Detection and Degradation Monitoring of Brilliant Green

Abstract

The present research work aims to contribute toward the sustainable development goal of water cleanliness by monitoring and removing toxic effluents from wastewater. Herein, we present an electrochemical sensing platform made of a glassy carbon electrode modified with Fe-doped ZnO nanoparticles (NPs) and multiwalled carbon nanotubes (MWCNTs) for the detection of brilliant green (BG) using a smart droplet analysis approach. The Fe−ZnO NPs were synthesized via a hydrothermal method and characterized by various analytical techniques such as UV−visible spectroscopy, XRD, SEM, EDX, and FTIR spectroscopy. Fe−ZnO NPs were found to act as a mediator between the transducer and BG for efficient electron transport, while MWCNTs led to the enhanced current response of BG at the electrode surface owing to their conductive and adsorptive characteristics. Under optimized conditions of pH 6, 0.1 V deposition potential, and 40 s deposition time, a 0.40 nM limit of detection was achieved at the designed nanosensor. Photocatalytic degradation of the dye with NPs was also investigated in different pH media using UV−visible spectroscopy. The dye was found to photocatalytically degrade up to 99% in just 30 min, following firstorder kinetics with a rate constant of 0.14 min −1 . The photocatalytic degradation was also monitored electrochemically at the designed sensing platform, and the findings were found to be in good agreement with the results of UV−visible spectroscopy. The developed electrochemical droplet analysis approach is not only economical but also efficient, ultra-sensitive, and environmentally friendly.

Photoelectrocatalytic Detection and Degradation Studies of a Hazardous Textile Dye Safranin T

“…The X-ray diffractograms of pristine ZnO and Fe-ZnO NPs are presented in Figure 1A. All observed XRD peaks are in good agreement with the reported literature (JCPDS 36-1451), corresponding to a pure hexagonal wurtzite structure [40]. The XRD pattern of Fe-ZnO NPs showed no additional peaks, which indicates that Fe ions are well integrated into the Zn crystal lattice without producing any disturbance in the crystal structure of ZnO NPs, and no evidence of impurities of the secondary phase (Fe 2 O 3 and pure Fe) is observed.…”

“…Electrochemical sensors based on COOH-f MWCNTs have been reported for a variety of analytes [38,39]. The coupling of CNTs with nanoparticles has been reported to further enhance the sensing characteristics of the modified electrode surface, which can be attributed to the provision of greater active surface area for analyte adsorption at their surface [40].…”

Target-Imprinted Polyaniline/Nb2O5 Nanoparticles as Electrochemical Interfaces for Monitoring Kidney Function

“…For all sensors, the anodic peak current ( I pa ) increases as a function of the applied scan rate ( v ), as shown in Figure S6. The slope of the calibration curve, i.e., the logarithm of I pa plotted against the logarithm of v , represents either an adsorption or surface-controlled process (slope = 1.0), or a diffusion-controlled process (slope = 0.5). , Figure S7 shows the calibration curves (log I pa vs log v ) of PAni, Cre-PAni, and PAni/Nb 2 O 5 sensors. With a slope value of 1.0, nonimprinted PAni and PAni/Nb 2 O 5 exhibit surface-controlled redox processes, limited by charge transfer across the interface, while imprinted Cre-PAni exhibits a slope value of 0.94, signifying a limited contribution of diffusion-controlled processes along with predominant surface-controlled reactions simultaneously. , …”

Characteristics and Applicability Analysis of Nanomorphological Structures for Chemosensors: A Systematic Review

“…Research related to MWCNTs includes electrochemical performance, sensors, thin films, electrocatalysts, batteries, etc. [100][101][102][103][104][105].…”