Adsorbent-Assisted In Situ Electrocatalysis: Highly Sensitive and Stable Electrochemical Sensor Based on AuNF/COF-SH/CNT Nanocomposites for the Determination of Trace Cu(II)

Abstract

The weak conductivity of covalent organic frameworks (COFs) limits their wide application in electrochemical sensors. Here, a novel electrochemical sensor (AuNFs/COF-SH/CNTs/GCE) was designed and constructed by a one-step electrochemical deposition of Au nanoflowers (AuNFs) on a hybrid nanocomposite of sulfhydryl-functional covalent organic framework/carbon nanotubes (COF-SH/CNTs) for the determination of Cu(II) in seawater. AuNFs/COF-SH/CNTs/GCE was prepared in a three-step method including in situ synthesis, post-synthesis, and one-step electrochemical deposition. The adsorption and catalytic performances of the modified electrode were improved based on the mechanism of “adsorption-catalysis stripping determination”. By combining the excellent catalytic properties of the AuNFs with the good adsorption capacity of COF-SH toward Cu(II), as well as the good conductivity of CNTs, the AuNFs/COF-SH/CNTs/GCE exhibited excellent performance for the determination of Cu(II). Through optimization of the experimental conditions, a low detection limit of 0.47 nM and a wide linear range of 1.6 nM-4.7 μM were obtained. Moreover, the sensor possessed good stability with a relative standard deviation of less than 5% after 20 repeated measurements. The results are consistent with certified values when used for the determination of certified reference materials. In summary, the AuNFs/COF-SH/CNTs/GCE, with high stability and sensitivity, has been successfully applied for the determination of Cu(II) in seawater samples with satisfactory results.

Covalent Organic Frameworks/MWCNT Nanocomposites for Electrochemical Detection of the H1N1 Influenza Virus

“…As shown in Figure a,b, the electrochemical properties of bare GCE, COFs, and COFs/MWCNTs were characterized by CV and EIS, demonstrating that the COFs/MWCNT nanocomposites exhibited improved electrochemical performances. Currently, COFs/CNT hybrid materials have been used to construct electrochemical biosensors, such as AuNF/COF-SH/CNT nanocomposites, COF/MWCNTs/CLS nanocomposites, TFPPy-BD-COF/MWCNT nanocomposites, and so on have been prepared. − Therefore, COFs/MWCNTs have been introduced in our work to reduce the impedance of sensing materials. The CV curves at different scan rates were further used to calculate the electroactive surface areas of COFs and COFs/MWCNTs, and as could be seen in the redox peaks, the peak currents increased gradually with the increase in scan rates (Figure S6a,c).…”

Post-synthetic modifications of covalent organic frameworks (COFs) for diverse applications

“…The promoted conductivity of this electrochemical sensor was confirmed by cyclic voltammetry (CV). 95 Another class of water contaminants is non-steroidal anti-inflammatory drugs (NSAIDs). NSAIDs are commonly prescribed for pain relief and inflammatory control.…”