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Tuning the electroreduction of NO3−vis-à-vis Bi3+ results in nano-/micro-hexagons. Nanohexagons are highly sensitive to trace detection of lead.

The fabrication of nanocomposites is essential because a multiphase interface delivers highly sensitive and selective method for the individual and simultaneous electrochemical determination of drugs. Herein, we introduce an electrochemical sensor using Pt/CeO2@Cu2O nanocomposites for simultaneous detection of dopamine (DA) and paracetamol (PA), which were synthesized using a low temperature clean aqueous phase additives-free method with Cu2O as sacrificial template. We investigated the electrochemical behavior of the various modified electrodes by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), in which Pt/CeO2@Cu2O proved to be highly sensitive and selective toward individual and simultaneous detection of DA and PA. Sensitive electrooxidation peak potential at 160 mV and 380 mV from the DPV technique was observed for DA and PA, respectively. Both DA and PA exhibit linear response over the range of 0.5 μM to 100 μM. The stability, reproducibility, and repeatability of the Pt/CeO2@Cu2O were also inspected. The lower detection limits of 0.079 μM and 0.091 μM were recorded for DA and PA, respectively. The practical applicability of the Pt/CeO2@Cu2O–carbon paste electrode (CPE) is toward the simultaneous detection of DA and PA in drugs, as well as in spiked human serum and urine samples.

Development of highly active and stable low-cost Pt-free catalysts for ethanol electrooxidation (EOR) in alkaline medium has drawn a lot of attention in recent years. Palladium-based catalysts are on the forefront of this research. Pd 2 Ge, previously developed by our group, is a highly active and stable catalyst for EOR because of its ordered structure and the presence of Ge. In this work, we used it as a platform to further enhance its efficiency by Ni substitution (Pd 2−x Ni x Ge), which shifts the d-band center of the catalysts toward the Fermi level with the increasing binding energy toward the adsorbate. Stronger interaction between the Ni, Pd, and Ge atoms leads to stronger adsorption of −OH intermediates (−436 kJ/mol) and weaker adsorption of −CH 3 CO (−220 kJ/mol). As a result, this catalyst exhibits 3.8 times higher mass activity and 70 mV lower onset potential than pristine Pd 2 Ge for EOR in alkaline media.

This work reports a graphene-based nonenzymatic electrochemical sensing platform for the detection of dopamine (DA), uric acid (UA), and ascorbic acid (AA). Graphene oxide, synthesized by modified Hummers method, was thermally reduced in an induction furnace at 200 °C in an Ar-H2 atmosphere to obtain thermally reduced graphene oxide (tRGO). Nanocomposites of tRGO-TiO2 were obtained by a hydrothermal method, and were characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD). FTIR spectra showed Ti-O-C peaks, indicating covalent linkage between the TiO2 nanoparticles and the reduced graphene oxide sheets. Glassy carbon electrode (GCE) was modified with the nanocomposite (tRGO-TiO2-GCE), and the modified electrode could detect dopamine (DA: 1 to 1000 µM), uric acid (UA: 1 to 900 µM), and ascorbic acid (AA: 10 to 1000 µM) in each other's presence over wide ranges, with adequate separation in peak potentials. Differential pulse voltammetry experiments yielded linear responses with sensitivities of 133.18, 33.96, and 155.59 µA mM(-1) cm(-2) for DA, UA, and AA, respectively.

Electrodeposition of tin-bismuth alloys on polycrystalline copper electrodes has been studied from an acidic bath comprising SnCl4, Bi(NO3)3, citric acid, poly(vinyl alcohol) and betaine. Using linear sweep voltammetry (LSV) and chronoamperometry (CA), co-deposition of tin and bismuth from the above bath has been examined. Bismuth (III) ions get reduced in a single-step, three-electron-transfer reaction while tin (IV) ions undergo a two-step reduction through the formation of tin (II) ions. Nitric acid in the bath not only enhances solubility of the precursors but also decreases the peak potential separation between bismuth (III) and tin (II) ions. Through the introduction of various additives and variation in bath pH, co-deposition is preserved while the composition of tin in the obtained alloy is modified. The morphologies, composition and crystallinity of the deposits have been determined using scanning electron microscopy, inductively coupled plasma atomic emission spectroscopy and X-ray diffraction, respectively. A wide range of alloy compositions (from 14% to 75% tin), including the eutectic Sn-Bi alloy have been deposited. Novel morphologies such as yarns-of-spool have been obtained.

The ability of a room-temperature air-atmosphere (RTAA) co-precipitation method to tune the magnetic properties of iron oxide nanoparticles was investigated. It was demonstrated that superparamagnetic nanoparticles with different particle sizes ranging from 7 to 25 nm and magnetic properties with saturation magnetization between 2 to 75 emu g(-1) can be synthesized by simply controlling the molar ratio of ferrous to ferric ions and the concentration of ammonium solution, without heat treatment or oxygen-level control. It was revealed that the tuning of the magnetic properties was associated with the compositional control between magnetite and maghemite. Ammonium concentration was also an important factor to obtain dispersed superparamagnetic (SPM) or ferrimagnetic (FM) nanoparticles.

Covalently anchored chromium complex on reduced graphene oxide (rGO‐Cr) is successfully synthesised through trimethoxy silyl propanamine (TMSPA) and phenyl azo salicylaldehyde (PAS) coupling. The rGO‐Cr is characterised by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), electron dispersive analysis of X‐rays (EDAX), Raman spectroscopy, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Absorption and emission properties of rGO‐TMSPA‐PAS are studied by excitation dependent photoluminescence emissions at room temperature. Electrochemical sensing activity of rGO‐Cr is monitored for paracetamol using modified glassy carbon electrode. Cyclic voltammetry measurements indicated that rGO‐Cr substantially enhance the eletrochemical response of paracetamol. The experimental factors are investigated and optimized.