Single-Fe-Atom Catalyst for Sensitive Electrochemical Detection of Caffeic Acid

Abstract

A single-atom catalyst (Fe SAs/–N-C) with excellent stability and conductivity was strategically fabricated via high-temperature calcination using the NiFe layered double hydroxide (LDH)/ZIF-8 composite as precursors. With the help of Ni as a catalyst, a great number of carbon nanotubes were produced whereby the isolated carbon bulks were interconnected to form an “island-bridge”-like 3D network structure, which greatly enhanced the exposure of active sites and the electron transfer. Accordingly, caffeic acid (CA) with versatile biological and pharmacological activities was chosen as the model analyte. The Fe SAs/–N-C with Fe–N4 as the catalytic active site was employed to establish the electrochemical sensing of CA with satisfactory sensitivity, selectivity, and long-term stability. This work expands the application range of single-atom catalysts and contributes a significant reference for the synthesis of hybrid double-atom catalysts.

Robust Activity and Stability of P-Doped Fe–Carbon Composites Derived from MOF for Bromate Reduction

“… ,,, The presence of P–C bonds and P–Fe bonds indicates the successful doping of P atoms into the carbonaceous matrix and the formation of Fe–P coordination, evidenced by the presence of XPS peaks at 285.5 eV from C–P bonds in the C 1s region and 707.4 eV from Fe–P bonds in the Fe 2p region (Figure S6). , The N 1s spectra are further deconvoluted into five N species at 398.4 eV (pyridinic N), 399.5 eV (N–Fe), 400.6 eV (pyrrolic N), 401.4 eV (graphitic N), and 403.8 eV (oxidized N) (Figures d and S7) ,,, . The corresponding fitting parameters of P 2p and N 1s are summarized in Tables S2 and S3.…”

Efficient Multi-stimulus-Responsive Luminescent Eu(III)-Modified HOFs Materials: Detecting Thiram and Caffeic Acid and Constructing a Flexible Substrate Anti-counterfeiting Platform

“…CA is a phenolic acid commonly found in vegetables, fruits, and wine and exhibits various pharmacological effects; nevertheless, high concentrations of caffeic acid have been shown to be cytotoxic and even carcinogenic …”

“…CA is a phenolic acid commonly found in vegetables, fruits, and wine and exhibits various pharmacological effects; 48 nevertheless, high concentrations of caffeic acid have been shown to be cytotoxic and even carcinogenic. 66 To investigate the ability of Eu@GC-2 to detect CA, 2 mg of Eu@GC-2 powder was added to CA solutions with different concentration gradients (from 5 × 10 −7 to 1.5 × 10 −3 M). In Figure 4b, the emission intensity at 614 nm noticeably decreased as the concentration increased, causing the emission light of the mixed solution to shift from red to mauve under the UV lamp.…”

Waveform Optimization for the In Vitro Detection of Caffeic Acid by Fast-Scan Cyclic Voltammetry

“…Because of its importance, various instrumental methods are available for detecting caffeic acid including ultraviolet–visible (UV–vis), fluorescence, and Raman spectroscopies, chromatography, and electrophoresis. − The presence of the catechol moiety within caffeic acid makes it electrochemically active, capable of undergoing a two electron, two proton reduction into caffeic acid o-quinone as shown in Scheme . Indeed, there have been several publications in recent years demonstrating cyclic, square wave, and differential pulse voltammetric approaches capable of measuring caffeic acid, with a focus on chemically modified and nanodecorated macroelectrodes. ,− Several recent works have also published comparisons of analytical figures of merit across these various approaches, highlighting nM detection limits or lower available for caffeic acid detection. ,,,− …”