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Ferrocene (Fc) is a widely used metallocene, with well‐characterized redox behaviour that is vastly used in a variety of applications. Ferrocene‐coupling to peptides renders the resulting bioorganometallic peptide conjugate redox active and sensitive to changes in the chemical environment. The disulfide‐linked ferrocene peptide conjugate (FcCO‐Phe‐Cys‐OH)2 was synthesized and characterized by NMR, MS, and FT‐IR spectroscopies and then exploited for the detection of ascorbic acid. Here we demonstrate that the Cu(II) complex of this peptide conjugate allows the detection of ascorbic acid with a limit of detection of 0.02 μM with a linear range of 0.1–25 μM. This is the first report of the use of a peptide metal complex for direct modification of a glass carbon electrode and its application for ascorbic acid detection and quantification, including in commercial beverages. The modified GCE exhibited excellent selectivity, stability, and sensitivity. [ABSTRACT FROM AUTHOR]

Poly (4-vinyl pyridine) cross-linked by 2%DVB quartenized by I−, Br−, N3− and SCN−; named [P4-VP]MI, [P4-VP]BBr, [P4-VP]MN3, [P4-VP]MSCN are synthesized and their effect as a new eco-friendly polymeric inhibitor on the corrosion process of St-37 in 1 M H2SO4 at ambient temperature was investigated. Fourier-transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX) and scanning electron microscope (SEM) techniques are used to confirm formation and the structure of the inhibitors. Then, their ability as corrosion inhibitors are examined by theoretical computation as well as the experimental tests involving potentiodynamic polarization (PDP), weight-loss measurements and electrochemical impedance spectroscopy (EIS). According to the obtained results, all inhibitors can effectively protect carbon steel from corrosion and the inhibition efficiency increases as the concentration of inhibitor and reaching 91.08% at 0.04 g L−1 [P4-VP]MI in 1 M H2SO4 and the corrosion current density reduces from 398.11 × 10−6 A·cm−2 in the blank condition to 35.48 × 10−6 A·cm−2. The geometrical and electronic properties of poly(4-vinylpyridine) cross-linked with 2% divinyl benzene and its derivatives as well as their corrosion inhibition process on Fe (1 1 0) surface are investigated using density-functional theory (DFT) and molecular dynamics (MD) simulation in water solution. The results of comparing the inhibitory efficiency of polymers show that the order of inhibition is as follows: [P4-VP]MI > [P4-VP]BBr > [P4-VP]MN3 > P4-VP > [P4-VP]MSCN. [ABSTRACT FROM AUTHOR]

In this proof-of-concept study, gold nanoparticles (AuNPs) were immobilized on glassy carbon electrode (GCE) surfaces using a surface-anchored diazonium salt of 4-aminothiophenol (GCE-Ph-S-AuNPs). X-ray photoelectron spectroscopy (XPS) studies confirmed the attachment of the AuNPs via 4-thiophenol onto the surface of the modified electrode. Differential pulse voltammetry (DPV) was performed for the simultaneous determination of guanine (G) and 8-hydroxyguanine (8-OH-G). The calibration curves were linear up to 140 µM and 60 µM with a limit of detection of 0.02 µM and 0.021 µM for G and 8-OH-G, respectively. Moreover, chronoamperometric studies were carried out for the determination of diffusion coefficients of 8-OH-G and G. The GCE-Ph-S-AuNPs were also applied in genomic DNA-spiked samples for the determination of G and 8-OH-G with recovery rates between 98.5% and 103.3%. The novel electrochemical surface provided a potential platform for the sensitive detection of 8-OH-G related to oxidative stress-induced DNA damage in clinical studies. [ABSTRACT FROM AUTHOR]

The electrochemical CO2 reduction reaction (CO2RR) is an attractive method to produce renewable fuel and chemical feedstock using clean energy sources. Formate production represents one of the most economical target products from CO2RR but is primarily produced using post‐transition metal catalysts that require comparatively high overpotentials. Here a composition of bimetallic Cu–Pd is formulated on 2D Ti3C2Tx (MXene) nanosheets that are lyophilized into a highly porous 3D aerogel, resulting in formate production much more efficient than post‐transition metals. Using a membrane electrode assembly (MEA), formate selectivities >90% are achieved with a current density of 150 mA cm−2 resulting in the highest ever reported overall energy efficiency of 47% (cell potentials of −2.8 V), over 5 h of operation. A comparable Cu‐Pd aerogel achieves near‐unity CO production without the MXene templating. This simple strategy represents an important step toward the experimental demonstration of 3D‐MXenes‐based electrocatalysts for CO2RR application and opens a new platform for the fabrication of macroscale aerogel MXene‐based electrocatalysts. [ABSTRACT FROM AUTHOR]