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.

Development of a Toxic Lead Ionic Sensor Using Carboxyl-Functionalized MWCNTs in Real Water Sample Analyses

Functional multiwall carbon nanotubes (f-MWCNTs) are of significant interest due to their dispersion ability in the aqueous phase and potential application in environmental, nanotechnology, and biological fields. Herein, we functionalized MWCNTs by a simple acid treatment under ultra-sonification, which represented a terminal or side-functional improvement for the fabrication of a toxic lead ion sensor. The f-MWCNTs were characterized in detail by XRD, Raman, XPS, BET, UV/vis, FTIR, and FESEM-coupled XEDS techniques. The analytical performance of the f-MWCNTs was studied for the selective detection of toxic lead ions by inductively coupled plasma-optical emission spectrometry (ICP-OES). The selectivity of the f-MWCNTs was evaluated using several metal ions such as Cd²⁺, Co²⁺, Cr³⁺, Cu²⁺, Fe³⁺, Ni²⁺, Pb²⁺, and Zn²⁺ ions. Lastly, the newly designed ionic sensor was successfully employed to selectively detect lead ions in several environmental water samples with reasonable results. This approach introduced a new technique for the selective detection of heavy metal ions using functional carbon nanotubes with ICP-OES for the safety of environmental and healthcare fields on a broad scale.

Fabrication of Novel and Potential Selective 4-Cyanophenol Chemical Sensor Probe Based on Cu-Doped Gd2O3 Nanofiber Materials Modified PEDOT:PSS Polymer Mixtures with Au/µ-Chip for Effective Monitoring of Environmental Contaminants from Various Water Samples

Herein, a novel copper-doped gadolinium oxide (Cu-doped Gd2O3; CGO) nanofiber was synthesized by a simple solution method in the basic phase and successfully characterized. We have used Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Energy-Dispersive Spectroscopy (EDS) techniques for characterization of the CGO nanofiber. The CGO nanofiber was used later to modify Au-coated μ-Chips with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) polymer mixtures (coating binder) to selectively detect 4-cyanophenol (4-CP) in an aqueous medium. Notable sensing performance was achieved with excellent sensitivity (2.4214 µAµM-1 cm-2), fast response time (~12 s), wide linear dynamic range (LDR = 1.0 nM-1.0 mM: R2 = 0.9992), ultra-low detection limit (LoD; 1.3 ± 0.1 pM at S/N = 3), limit of quantification (LoQ; 4.33 pM), and excellent reproducibility and repeatability for CGO/Au/μ-Chip sensor. This CGO modified Au/μ-chip was further applied with appropriate quantification and determination results in real environmental sample analyses.

Electrochemical Detection of Hydrazine by Carbon Paste Electrode Modified with Ferrocene Derivatives, Ionic Liquid, and CoS2-Carbon Nanotube Nanocomposite

The electrocatalytic performance of carbon paste electrode (CPE) modified with ferrocene-derivative (ethyl2-(4-ferrocenyl[1,2,3]triazol-1-yl)acetate), ionic liquid (n-hexyl-3-methylimidazolium hexafluorophosphate), and CoS2-carbon nanotube nanocomposite (EFTA/IL/CoS2-CNT/CPE) was investigated for the electrocatalytic detection of hydrazine. CoS2-CNT nanocomposite was characterized by field emission scanning electron microscopy, X-ray powder diffraction, and transmission electron microscopy. According to the results of cyclic voltammetry, the EFTA/IL/CoS2-CNT-integrated CPE has been accompanied by greater catalytic activities for hydrazine oxidation compared to the other electrodes in phosphate buffer solution at a pH 7.0 as a result of the synergistic impact of fused ferrocene-derivative, IL, and nanocomposite. The sensor responded linearly with increasing concentration of hydrazine from 0.03 to 500.0 μM with a higher sensitivity (0.073 μA μM-1) and lower limit of detection (LOD, 0.015 μM). Furthermore, reasonable reproducibility, lengthy stability, and excellent selectivity were also attained for the proposed sensor. Finally, EFTA/IL/CoS2-CNT/CPE was applied for the detection of hydrazine in water samples, and good recoveries varied from 96.7 to 103.0%.

Photocatalysis, photoinduced enhanced anti-bacterial functions and development of a selective m-tolyl hydrazine sensor based on mixed Ag·NiMn2O4 nanomaterials

In this work, a tri-metal based nanocomposite was synthesized and characterized. A detailed investigation of the photocatalytic dye degradation efficiency of the nanocomposite under visible light showed promising results in a wide pH range, both acidic and basic medium. Studies on anti-bacterial activity against seven pathogenic bacteria, including both Gram positive and Gram negative species, were conducted in the presence and absence of light and compared with the standard antibiotic gentamicin. The minimum inhibitory concentration (MIC) values of Ag·NiMn₂O₄ against multidrug-resistant (MDR) pathogens ranged from 0.008 to 0.65 μg μL^-1, while the minimum bactericidal concentration (MBC) was found to be 0.0016 μg μL^-1. The nanomaterial, Ag·NiMn₂O₄ was deposited onto the surface of a glassy carbon electrode (GCE; 0.0316 cm²) as a thin film to fabricate the chemical sensor probe. The proposed sensor showed linear current (vs. concentration) response to m-THyd (m-tolyl hydrazine) from 1.0 pM to 0.01 mM, which is denoted as the linear dynamic range (LDR). The estimated sensitivity and detection limit of the m-THyd sensor were found to be 47.275 μA μM^-1 cm^-2 and 0.97 ± 0.05 pM, respectively. As a potential sensor, it is reliable due to its good reproducibility, rapid response, higher sensitivity, working stability for long duration and efficiency in the analysis of real environmental samples.

Electrocatalytic Oxidation of 4-Aminophenol Molecules at the Surface of an FeS2 /Carbon Nanotube Modified Glassy Carbon Electrode in Aqueous Medium

FeS₂ /carbon nanotube (CNT) nanocomposites were synthesized and immobilized on the surface of a glassy carbon electrode (GCE) in order to investigate the electrocatalytic conversion of 4-aminophenol (4-AP) into p-quinone in an aqueous medium. The reformed electronic properties (in terms of lowering of band-gap energy and charge-transfer resistance), as well as improved surface area, result in an enhanced redox reaction of 4-AP in the presence of FeS₂ -CNT NCs compared to that with FeS₂ alone. The 4-AP molecules undergo coupled two-proton and two-electron transfer quasi-reversible redox reactions with a symmetry factor of 0.55 and standard rate constant (k°) of 0.8 cm s^-1 . Here, quinone imine is generated as an intermediate which is later converted into quinone in an irreversible hydrolysis reaction. The best catalytic performance can be obtained at the pH value of 7.0.

Detection of 3,4-diaminotoluene based on Sr0.3Pb0.7TiO3/CoFe2O4 core/shell nanocomposite via an electrochemical approach

We reported a scalable sol–gel method for the preparation of Sr_0.3Pb_0.7TiO₃/CoFe₂O₄ core–shell magnetic nanocomposite with a finely controlled shell and evaluated its efficiency as an electrochemical sensor for the selective detection of 3,4-diaminotoluene.

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.

3-Methoxyphenol chemical sensor fabrication with Ag2O/CB nanocomposites

The proposed chemical sensor based on Ag₂O/CB nanocomposites is developed by electrochemical approach for the detection of hazardous selective 3-methoxyphenol chemical sensor for the safety of the environment sector in a broad scale.

Simultaneous detection of l-aspartic acid and glycine using wet-chemically prepared Fe3O4@ZnO nanoparticles: real sample analysis

An easy and reliable wet-chemical method was used to synthesize iron oxide doped zinc oxide nanoparticles (Fe₃O₄@ZnO NPs) at a low-temperature under alkaline medium.

Novel urchin-like FeCo oxide nanostructures supported carbon spheres as a highly sensitive sensor for hydrazine sensing application

Herein, we successfully fabricated a novel nanostructure based on hierarchical urchin-like FeCo oxide supported carbon spheres (FeCo Oxide/CSs) via a two-step hydrothermal method followed by a simple annealing step at 300 °C under air. It was found that such urchin-like FeCo Oxide/CSs structure exhibited superior catalytic activity towards hydrazine oxidation to CSs, Fe Oxide/CSs, Co Oxide/CSs, and FeCo Hydroxide/CSs material. In this regard, the FeCo Oxide/CSs displayed a wide linear detection range of 0.1-516.6 μM, low detection limit of 0.1 μM, and long-term stability. The material also showed good selectivity towards hydrazine detection in the presence of various interferences, such as uric acid, ascorbic acid, urea, dopamine, Na⁺, SO₄^2-, K⁺, and Cl-. The excellent sensing performance of the FeCo Oxide/CSs was assumed to the unique hierarchical urchin structure with the high density and uniformity of nano-sized FeCo Oxide nanoneedles, which produced massive electroactive sites and enhanced charge transfer ability. The achieved results implied that the FeCo Oxide/CSs may be a great candidate for sensitive hydrazine detection.

Defects and impurities induced structural and electronic changes in pyrite CoS2: first principles studies

Cobalt pyrite (CoS2) and related materials are attracting much attention due to their potential use in renewable energy applications. In this work, first-principles studies were performed to investigate the effects of various neutral defects and ion dopants on the structural, energetic, magnetic and electronic properties of the bulk CoS2. Our theoretical results show that the concentrations of single cobalt (VCo) and sulfur (VS) vacancies in CoS2 samples can be high under S-rich and S-poor conditions, respectively. Although the single vacancies induce defect states near the gap edge, they are still half-metallic. We find that the substitution of one S with the O atom does not obviously change the structural, magnetic and electronic features near the Fermi level of the system. Most transition metal impurities (MnCo, FeCo, and MoCo) and Group IV and V anion impurities (CS, SiS, NS, PS, and AsS) create impurity states that are deep and/or near the gap edge. However, NiCo and Group VII elements (FS, ClS, and BrS) cause very localized gap states close to the Fermi level in the minority spin channel, which may modify their electrochemical performances. Our extensive calculations provide instructive information for the design and optimization of CoS2-related energy materials.

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.

Selective hydrazine sensor fabrication with facile low-dimensional Fe2O3/CeO2 nanocubes

Here, the binary-doped metal oxides of Fe₂O₃/CeO₂ nanocubes were prepared using reliable hydrothermal process, which is applied to fabricate an efficient and selective hydrazine chemical sensor shows good analytical sensing performances as well as validated the sensor prove with the environmental and extracted real samples.

A highly selective long-wavelength fluorescent probe for hydrazine and its application in living cell imaging

A highly selective long-wavelength turn-on fluorescent probe has been developed for the detection of N₂H₄. The probe was prepared by conjugation the tricyanofuran-based D-π-A system with a recognizing moiety of acetyl group. In the presence of N₂H₄, the probe can be effectively hydrazinolysized and produce a turn-on fluorescent emission at 610nm as well as a large red-shift in the absorption spectrum corresponding to a color change from yellow to blue. The sensing mechanism was confirmed by HPLC, MS, UV-vis, emission spectroscopic and theoretical calculation studies. The probe displayed high selectivity and sensitivity for N₂H₄ with a LOD (limit of detection) of 0.16μM. Moreover, the probe was successfully utilized for the detection of hydrazine in living cells.

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.