A glassy carbon electrode modified with nanoporous PdFe alloy for highly sensitive continuous determination of nitrite

Iron-Palladium magnetic nanoparticles for decolorizing rhodamine B and scavenging reactive oxygen species

HYPOTHESIS

Here, FePd magnetic nanoparticles (MNPs) are developed as artificial enzymes with high biocompatibility and reusability.

EXPERIMENT

The nanoparticles (NPs) are synthesized in an aqueous solvent by one-pot synthesis utilizing glutathione (GSH) and cysteine (Cys) as surfactants.

FINDINGS

The prepared hydrophilic FePd NPs are redispersible in water. Further, they exhibit catalytic activity for the degradation of rhodamine B (RhB), as well as for the inhibition of reactive oxygen species (ROS) production induced by H₂O₂, which are two- and seven-fold enhancements of their catalytic performances, respectively, compared with that of horseradish peroxidase. The computational simulation and electrochemical analysis indicate that the enhancement of the catalytic effect is due to the protection of the MNP surface by GSH and Cys. In vitro experiments reveal that FePd MNPs behave like a peroxidase and decrease the ROS in mammalian cells. The cytotoxicity assessment of FePd MNPs via exposures to different cell lines for over seven days indicates that they can maintain the cell viability of >90% for up to 20 μgmL^-1 concentration. FePd MNPs with high saturation magnetization and biocompatibility can be utilized as recyclable peroxidase-mimicking nanozymes and biosensors in a variety of catalytic and biological applications.

Facile synthesis and characterization of erbium oxide (Er2O3) nanospheres embellished on reduced graphene oxide nanomatrix for trace-level detection of a hazardous pollutant causing Methemoglobinaemia

The nanomaterials have received enormous attention in the catalysis applications. Particularly, we have focused on the fabrication of nanocomposite for an electrochemical sensor with improved electrocatalytic performance. Herein, a rapid and sensitive electrochemical detection of nitrite is essential for assessing the risks facing ecosystems in environment. We report a simple and robust ultrasonic-assisted synthetical route via prepared Er₂O₃ nanoparticles decorated reduced graphene oxide nanocomposite (Er₂O₃ NPs@RGO) modified electrode for nitrite detection. The composition and morphological formation were characterized by XRD, XPS, FESEM, and HRTEM. The amperometric (i-t) and cyclic voltammetry were exhibits tremendous electrocatalytic capability and superior performance toward nitrite oxidation. A sensitive and reproducible amperometric nitrite sensor was fabricated which able to detect trace concentration as 3.69 nM and excellent sensitivity (24.17 µA µM^-1 cm^-2). The method worked well even in cured meat and water samples and the results has indicates the reliability of the method in real-time analysis.

Electrodeposition of Pd-Pt Nanocomposites on Porous GaN for Electrochemical Nitrite Sensing

In recent years, nitrite pollution has become a subject of great concern for human lives, involving a number of fields, such as environment, food industry and biological process. However, the effective detection of nitrite is an instant demand as well as an unprecedented challenge. Here, a novel nitrite sensor was fabricated by electrochemical deposition of palladium and platinum (Pd-Pt) nanocomposites on porous gallium nitride (PGaN). The obtained Pd-Pt/PGaN sensor provides abundant electrocatalytic sites, endowing it with excellent performances for nitrite detection. The sensor also shows a low detection limit of 0.95 µM, superior linear ampere response and high sensitivity (150 µA/mM for 1 to 300 µM and 73 µA/mM for 300 to 3000 µM) for nitrite. In addition, the Pd-Pt/PGaN sensor was applied and evaluated in the determination of nitrite from the real environmental samples. The experimental results demonstrate that the sensor has good reproducibility and long-term stability. It provides a practical way for rapidly and effectively monitoring nitrite content in the practical application.

Nanoporous PdCu alloy as an excellent electrochemical sensor for H2O2 and glucose detection

Nanoporous (NP) PdCu alloy is easily fabricated by dealloying PdCuAl ternary alloy in dilute sulfuric acid. Selectively dissolving Al from PdCuAl alloy generates the three-dimensional uniform nanosponge architecture with narrow ligament size distribution. Benefitting from the unique nanoporous architecture and the alloying effect, the as-made NP-PdCu exhibits outstanding sensing performance towards the detection of hydrogen peroxide (H₂O₂) and glucose. Compared with NP-Pd and commercial Pd/C catalysts, the NP-PdCu alloy presents high sensitivity, wide linear range of 0.1-2.0mM, low detection limit of 2.1μM, and long-term stability toward H₂O₂ detection. In addition, the NP-PdCu can efficiently detect glucose in a wide concentration range (1-30mM) with the low detection limit of 1.9μM. Moreover, the NP-PdCu exhibits good anti-interference toward ascorbic acid, uric acid, and dopamine. Characterized by easy preparation, unique electrocatalytic activity, and high structure stability, the NP-PdCu alloy possesses great application prospect to construct platform for electrochemical sensing.

Ultrafine FePd Nanoalloys Decorated Multiwalled Cabon Nanotubes toward Enhanced Ethanol Oxidation Reaction

Ultrafine iron-palladium (FePd) nanoalloys deposited on γ-Fe2O3, FePd-Fe2O3, further anchored on carboxyl multiwalled carbon nanotubes (MWNTs-COOH), FePd-Fe2O3/MWNTs, were successfully synthesized by a facile one-pot solution based method as thermally decomposing palladium acetylacetonate (Pd(acac)2) and iron pentacarbonyl (Fe(CO)5) in a refluxing dimethylformamide solution in the presence of MWNTs-COOH. A 3.65 fold increase of peak current density was observed in cyclic voltammetry (CV) for ethanol oxidation reaction (EOR) compared with that of Pd/MWNTs after normalizing to Pd mass. The greatly enhanced tolerance stability toward poisoning species and largely reduced charge transfer resistance were also obtained in chronoamperometry and electrochemical impedance spectroscopy due to the downward shifted d-band center of FePd alloy, easily formed oxygen containing species on Fe2O3, and the stabilizing role of the MWNTs.