Determination of hydrazine by polyNi(II) complex modified electrodes with a wide linear calibration range

Electrocatalysis Using Cobalt Porphyrin Covalently Linked with Multi-Walled Carbon Nanotubes: Hydrazine Sensing and Hydrazine-Assisted Green Hydrogen Synthesis

Acid-treated multi-walled carbon nanotube (MWCNT) covalently functionalized with cobalt triphenothiazine porphyrin (CoTriPTZ-OH) A3B type porphyrin, containing three phenothiazine moieties (represented as MWCNT-CoTriPTZ) is synthesized and characterized by various spectroscopic and microscopic techniques. The nanoconjugate, MWCNT-CoTriPTZ, exhibits a pair of distinct redox peaks due to the Co2+/Co3+ redox process in 0.1 M pH 7.0 phosphate buffer. Further, it electrocatalytically oxidizes hydrazine at a low overpotential with a high current. This property is advantageously utilized for the sensitive determination of hydrazine. The developed electrochemical sensor exhibits high sensitivity (0.99 µAµM-1cm-2), a low limit of detection (4.5 ppb), and a broad linear calibration range (0.1 µM to 3.0 mM) for the determination of hydrazine. Further, MWCNT-CoTriPTZ is exploited for hydrazine-assisted green hydrogen synthesis. The high efficiency of hydrazine oxidation is confirmed by the low onset potential (0.45 V (vs RHE)) and 0.60 V (vs RHE) at the current density of 10 mA.cm-2. MWCNT-CoTriPTZ displays a high current density (77.29 mA.cm-2) at 1.45 V (vs RHE).

Ti3AlC2 MAX Phase Modified Screen-Printed Electrode for the Fabrication of Hydrazine Sensor

Hydrazine is considered a powerful reducing agent and catalyst, showing diverse applications in agricultural industries, toxic degradation research, and wastewater management. Additionally, hydrazine can trigger some specific reactions when combined with suitable oxidants. Due to its highly polar nature, hydrazine can easily dissolve in alcohol, water, and various other polar solvents. Therefore, it can be extensively utilized in different areas of application and industries such as rocketry and various chemical applications. Despite its beneficial properties, hydrazine is unstable, posing significant risk due to its highly toxic nature. It is extremely hazardous to both human health and the environment. It can cause various illnesses and symptoms such as dizziness, temporary blindness, damage to the central nervous system, and even death when inhaled in sufficient quantities. Therefore, it is highly important to monitor the level of hydrazine to prevent its toxic and hazardous effects on human beings and the environment. In the present study, we discuss the simple fabrication of a disposable cost-effective and eco-friendly hydrazine sensor. We used a screen-printed carbon electrode, i.e., SPCE, as a base for the construction of a hydrazine sensor. The Ti3AlC2 MAX has been used as a suitable and efficient electrode material for the fabrication of disposable hydrazine sensors. We modified the active surface of the SPCE using a drop-casting approach. The resulting Ti3AlC2 MAX modified SPCE (Ti3AlC2@SPCE) has been utilized as an efficient and low-cost hydrazine sensor. Cyclic voltammetry, i.e., CV, and linear sweep voltammetry, viz., LSV, was employed as a sensing technique in this study. The optimization of pH and electrode material loading was conducted. The Ti3AlC2@SPCE exhibited excellent sensing performance toward hydrazine oxidation. A reasonable detection limit (0.01 µM) was achieved for hydrazine sensing. The fabricated sensor also demonstrated a reasonable linear range of 1-50 µM. This work provides the design and fabrication of simple disposable Ti3AlC2@SPCE as a suitable electrode for the determination of hydrazine using LSV technology.

MoS2/S@g-CN Composite Electrode for L-Tryptophan Sensing

L-tryptophan (L-TRP) is an essential amino acid responsible for the establishment and maintenance of a positive nitrogen equilibrium in the nutrition of human beings. Therefore, it is vital to quantify the amount of L-tryptophan in our body. Herein, we report the MoS2/S@g-CN-modified glassy carbon electrode for the electrochemical detection of L-tryptophan (L-TRP). The MoS2/S@g-CN composite was successfully synthesized using an efficient and cost-effective hydrothermal method. The physical and chemical properties of the synthesized composite were analyzed using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray analysis (EDX). The crystallite size of the composite was calculated as 39.4 nm, with porous balls of MoS2 decorated over the S@g-CN surface. The XPS spectrum confirmed the presence of Mo, S, O, C, and N elements in the sample. The synthesized nanocomposite was further used to modify the glassy carbon (GC) electrode (MoS2/S@g-CN/GC). This MoS2/S@g-CN/GC was used for the electrochemical detection of L-TRP using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. For the purpose of comparison, the effects of the scanning rate and the concentration of L-TRP on the current response for the bare GC, S@g-CN/GC, MoS2/GC, and MoS2/S@g-CN/GC were studied in detail. The MoS2/S@g-CN-modified GC electrode exhibited a rational limit of detection (LoD) of 0.03 µM and a sensitivity of 1.74 µA/ µMcm2, with excellent stability, efficient repeatability, and high selectivity for L-TRP detection.

Fabrication of a hydrazine chemical sensor based on facile synthesis of doped NZO nanostructure materials

In this approach, nickel-doped zinc oxide (NZO) nanostructure materials were synthesized by the solution method in the basic phase.

CoS2-decorated ionic liquid-functionalized graphene as a novel hydrazine electrochemical sensor

Cobalt disulfide-decorated ionic liquid-functionalized graphene nanocomposites were prepared herein and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The as-prepared nanocomposites were subsequently used to build a modified glassy carbon electrode serving as a hydrazine (N₂H₄) electrochemical sensor. The electrocatalytic performance of the prepared sensor towards the N₂H₄ oxidation reaction was evaluated by cyclic voltammetry (CV) and amperometric methods. A linear dependence was found between the oxidation peak current and the concentration of N₂H₄. Thus, linear calibration plots were obtained over wide linear ranges of 5-100 μM (R² = 0.9898) and 100-400 μM (R² = 0.9852), with a relatively low detection limit of 0.39 μM (S/N = 3). The prepared sensor exhibited good electrocatalytic performance (i.e., sensitivity, reproducibility, and selectivity) towards the detection of N₂H₄. The sensor was successfully used for the practical determination of N₂H₄ in lake water samples with satisfactory recoveries.

Ultrasensitive hydrazine sensor fabrication based on Co-doped ZSM-5 zeolites for environmental safety

Various Co-loaded ZSM-5 zeolites (Co-ZSM-5) were prepared and the details of their structural, morphological and elemental properties characterized by different conventional methods.

A glassy carbon electrode modified with γ-Ce2S3-decorated CNT nanocomposites for uric acid sensor development: a real sample analysis

γ-Ce₂S₃-decorated multi-walled carbon nanotube nanocomposite (Ce₂S₃-CNT NC) was synthesized by a wet chemical method in basic media.

Hydrophobicity effects in iron polypyridyl complex electrocatalysis within Nafion thin-film electrodes

Four polypyridyl redox catalysts Fe(bp)₃²⁺, Fe(ph)₃²⁺, Fe(dm)₃²⁺, and Fe(tm)₃²⁺ (with bp, ph, dm, and tm representing 2,2′-bipyridine, 1,10-phenanthroline, 4,4′-dimethyl-2,2′-bipyridine, and 3,4,7,8-tetramethyl-1,10-phenanthroline, respectively) are investigated for the electrocatalytic oxidation of three analytes (nitrite, arsenite, and isoniazid).

Development of highly-sensitive hydrazine sensor based on facile CoS2–CNT nanocomposites

Cobalt pyrite-decorated carbon nanotube nanocomposites (CoS₂–CNT NCs) were prepared by a simple wet-chemical method and applied for a selective and sensitive hydrazine sensor.

Non-enzymatic electrochemical sensing platform based on metal complex immobilized carbon nanotubes for glucose determination

Nickel salophen (where salophen is N,N′-bis(salicylidene)-1,2-phenylenediamine) is immobilized on multiwall carbon nanotubes. This new material is utilized for electrocatalytic oxidization and sensitive determination of glucose in human blood samples.