One-step Route Research Articles

A portable electrochemical sensor based on binary transition metal oxide (CoO/ZnO) for the evaluation of eugenol in real-time samples

We report a one-step hydrothermal synthesis route of synthesizing the binary transition metal oxide-based composite using zinc acetate and cobalt acetate precursors. A synthesized binary transition metal oxide-based composite is characterized to understand features of crystalline and structural arrangements, functionality, chemical composition, and surface morphologies using the XRD, FT-IR, XPS, FESEM, & HR-TEM techniques. The composite materials tend to show excellent morphology with spherical morphology. Owing to this, the synthesized binary transition metal oxide composite is then modified over the surface of the glassy carbon electrode (GCE) towards the electrochemical sensing of Eugenol (EUG). In this regard, the CoO/ZnO/GCE composite delivers much more improved electrocatalytic activity because of the synergistic features offered by the binary transition metal oxides due to their unique structural morphology, high surface area, and increased active sites which afford rapid electron transfer rate to the CoO/ZnO/GCE when compared to other electrodes. CoO/ZnO/GCE sensor of determining the (EUG) with a wider linear range of 0.049 – 179.8 µM possessed nanomolar level detection (LOD) of under DPV & LSV is calculated to be 4 nM & 7 nM along with sensitivity found to be 1.366 µA µM−1 cm−2 & 1.01 µA µM−1 cm−2. The proposed CoO/ZnO/GCE has better selectivity over interference studies, with practical feasibility features of repeatability, reproducibility, and storage stability. Real-time sample practical applicability with exceptional recoveries of 99 % for the clove sample and urine samples.

One stone three birds: Chestnut-like CoZn-LDH via one-step facile route for both energy conversion and storage

Herein, we prepared three-function chestnut-like CoZn-LDH by a facile one-step solvothermal method with excellent performance for energy conversion and storage. Specifically, the as-prepared products yielded outstanding water splitting performance (η10 = 160 mV for hydrogen evolution reaction and η50 = 330 mV for oxygen evolution reaction) and high areal specific capacitance (2.24 F cm−2 at 10 mA cm−2). In addition, according to the electrochemical measurements, the viewpoint for explaining the coexistence of three functions (oxygen evolution reaction, hydrogen evolution reaction and capacitive performance) in chestnut-like CoZn-LDH was proposed for the first time. Last but not least, this work definitely shed light on the construction of multifunctional material.

Facile one-step hydrothermal route to MSe/Mo3Se4 (M: Zn, Mn, and Ni)-based electrode materials for ultralong-life hybrid supercapacitors

Transition metal selenides have attracted great interest in electrochemical energy storage applications because of their good electrochemical activity and conductivity properties. Herein, we reported the metal molybdenum selenide (MSe/Mo3Se4 (M: Zn, Mn, and Ni)) electrode materials on their morphological and electrochemical properties by varying the metal ions via a facile hydrothermal technique. The effects of the structural, morphological, and surface area properties of the prepared powder materials on their electrochemical performance were studied. Owing to the hierarchical porous and unique interconnected structure, the nickel molybdenum selenide nanosheet spheres (NMS NSSs)-based electrode material delivered an excellent specific capacity value of 252 mAh g–1 at a current density of 1 A g–1. Moreover, the optimized NMS NSSs electrode exhibited outstanding cycling stability with a capacity retention of 80% and a corresponding coulombic efficiency of 99% after 80,000 cycles. Additionally, a pouch-type hybrid supercapacitor (HSC) device was assembled using NMS NSSs material as a positive electrode and activated carbon as a negative electrode in 1 M aqueous KOH electrolyte. Furthermore, the assembled HSC device exhibited superior energy and power density values as well as magnificent cycling stability. For real-time practical applications, light-emitting diodes and a digital display were powered using two series-connected HSC devices. Therefore, the obtained tremendous results strongly suggest that the NiSe/Mo3Se4 NSSs-based materials could be a promising electrode for ultralong-life energy storage applications.

Efficient Removal of Congo Red, Methylene Blue and Pb(II) by Hydrochar–MgAlLDH Nanocomposite: Synthesis, Performance and Mechanism

Organic dyes and heavy metals often coexist in industrial effluents, and their simultaneous removal is a grand challenge. Herein, a hydrochar and MgAl layered double hydroxide (HC-MgAlLDH) nanocomposite was prepared via a facile one-step hydrothermal route, and applied to remove anionic Congo red (CR), cationic Methylene blue (MB) and Pb(II) from aqueous solutions. The nanocomposite was formed by interweaving amorphous HC and crystalline MgAlLDH nanoplates and possessed more functional groups, lower zeta potential and larger specific surface area than uncomposited MgAlLDH. Batch removal experiments showed that the components HC and LDH dominated the CR and MB removals, respectively, whereas Pb(II) removal was conjointly controlled by the two components. The maximum Langmuir removal capacities of the nanocomposite to sole CR, MB, or Pb(II) were 348.78, 256.54 or 33.55 mg/g. In binary and ternary systems, the removal capacities of CR and MB only slightly decreased, while the capacity of Pb(II) increased by 41.13-88.61%. The increase was related to the coordination of Pb(II) with the sulfur-containing groups in dyes and the precipitation of PbSO4. Therefore, the simultaneous removal of CR, MB and Pb(II) was involved in a synergistic effect, including electrostatic adsorption, π-π interaction, coordination and precipitation. The present work shows that the HC-MgAlLDH nanocomposite has great potential for wastewater integrative treatment.

Facile Synthesis of Battery-Type CuMn2O4 Nanosheet Arrays on Ni Foam as an Efficient Binder-Free Electrode Material for High-Rate Supercapacitors.

The development of battery-type electrode materials with hierarchical nanostructures has recently gained considerable attention in high-rate hybrid supercapacitors. For the first time, in the present study novel hierarchical CuMn2O4 nanosheet arrays (NSAs) nanostructures are developed using a one-step hydrothermal route on a nickel foam substrate and utilized as an enhanced battery-type electrode material for supercapacitors without the need of binders or conducting polymer additives. X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques are used to study the phase, structural, and morphological characteristics of the CuMn2O4 electrode. SEM and TEM studies show that CuMn2O4 exhibits a nanosheet array morphology. According to the electrochemical data, CuMn2O4 NSAs give a Faradic battery-type redox activity that differs from the behavior of carbon-related materials (such as activated carbon, reduced graphene oxide, graphene, etc.). The battery-type CuMn2O4 NSAs electrode showed an excellent specific capacity of 125.56 mA h g-1 at 1 A g-1 with a remarkable rate capability of 84.1%, superb cycling stability of 92.15% over 5000 cycles, good mechanical stability and flexibility, and low internal resistance at the interface of electrode and electrolyte. Due to their excellent electrochemical properties, high-performance CuMn2O4 NSAs-like structures are prospective battery-type electrodes for high-rate supercapacitors.

Synthesis of KH550-Modified Hexagonal Boron Nitride Nanofillers for Improving Thermal Conductivity of Epoxy Nanocomposites.

In this work, KH550 (γ-aminopropyl triethoxy silane)-modified hexagonal boron nitride (BN) nanofillers were synthesized through a one-step ball-milling route. Results show that the KH550-modified BN nanofillers synthesized by one-step ball-milling (BM@KH550-BN) exhibit excellent dispersion stability and a high yield of BN nanosheets. Using BM@KH550-BN as fillers for epoxy resin, the thermal conductivity of epoxy nanocomposites increased by 195.7% at 10 wt%, compared to neat epoxy resin. Simultaneously, the storage modulus and glass transition temperature (Tg) of the BM@KH550-BN/epoxy nanocomposite at 10 wt% also increased by 35.6% and 12.4 °C, respectively. The data calculated from the dynamical mechanical analysis show that the BM@KH550-BN nanofillers have a better filler effectiveness and a higher volume fraction of constrained region. The morphology of the fracture surface of the epoxy nanocomposites indicate that the BM@KH550-BN presents a uniform distribution in the epoxy matrix even at 10 wt%. This work guides the convenient preparation of high thermally conductive BN nanofillers, presenting a great application potential in the field of thermally conductive epoxy nanocomposites, which will promote the development of electronic packaging materials.

Photochemical Synthesis of Porous Triazine-/Heptazine-Based Carbon Nitride Homojunction for Efficient Overall Water Splitting.

Porous triazine-/heptazine-based carbon nitride (THCN) homojunction with chloride (Cl) doping was synthesized by a simple, one-step photochemical synthesis route for efficient visible-light-driven overall water splitting. The phase ratio of triazine-based carbon nitride (TCN) and heptazine-based carbon nitride (HCN), texture and morphology of the THCN isotype junction were finely tuned by varying ultraviolet irradiation time and washing solvents. After washing with acetonitrile, the resulting porous THCN nanosheets with 48 h irradiation contain 21 wt % TCN and 79 wt % HCN units and reveal a significantly improved photocatalytic performance with H2 and O2 production rates up to 7.9 and 4.2 μmol h-1 , respectively, about 3.8 times higher than that of THCN prepared by 36 h illumination. The dual-phase interaction, holey structure, and Cl dopants favor the exposure of active sites, extended visible-light harvesting, accelerated charge transfer, and enhanced photoreduction ability, thereby improving photocatalytic activity.

BiVO4-Decorated Graphite Felt as Highly Efficient Negative Electrode for All-Vanadium Redox Flow Batteries

Recently, discovering high-performance electrocatalytic materials for vanadium redox flow batteries (VRFBs) has been one of the most crucial tasks. This paper details the successful fabrication of a low-cost platelike bismuth vanadate (BiVO4) material through a simple one-step hydrothermal route, employed as an electrocatalyst to adorn graphite felt (GF) for use as the negative electrode in VRFBs. The experimental results show that BiVO4-3h exhibits the optimal electrocatalytic activity and reversibility for the vanadium redox couples among all samples. The energy efficiency of the VRFB cell assembled with BiVO4-decorated GF as the negative electrode is found to be 75.42% at 100 mA cm–2, which is about 10.24% more efficient than that of the cell assembled with a heat-treated graphite felt (HT-GF) electrode. The possible reasons for the activity enhancement can be ascribed to the existence of oxygen vacancies in the BiVO4 lattice structure and the relatively high surface area of BiVO4, which provide more active sites for facilitating the vanadium redox reactions. Furthermore, the BiVO4-GF electrode obstructs the competitive irreversible hydrogen evolution reaction on the negative side of the cell, and it also has better wettability. Impressively, BiVO4-GF as the negative electrode shows good stability over 100 cycles.

Ammonia sensing properties of PPy nanostructures (urchins/flowers) towards low-cost and flexible gas sensors at room temperature

High-performance room-temperature gas sensors have tremendous potential in real-world applications like air quality control, food safety, and health monitoring. In this work, we report an eco-friendly and one-step route for the chemical synthesis of hierarchical polypyrrole (PPy) nanotubes assembled urchins and flower-like nanostructures via a template-assisted method and examine their morphology-dependent gas sensing characteristics. The ammonia sensor was mounted on low-cost and highly flexible polyvinylidene fluoride (PVDF) membrane substrate for the fabrication of flexible sensor. The polypyrrole urchins and flower-like nanostructures exhibited high surface area of 194.9 m2/g and 101.05 m2/g along with highly porous structure confirmed by BET and SEM characterization. The nanotubes assembled urchin-like structure of PPy exhibited great response, repeatability, and long-term durability to NH3 gas in the range of 1–200 ppm owing to their high porosity, excellent flexibility, and large surface area. In addition, the PPy urchins based sensor exhibited low response time (23 s) and very high response of 34.7% towards 100 ppm concentration of ammonia gas at room temperature. From the flexibility point of view, proposed flexible sensor showed high mechanical robustness under extreme bending conditions, i.e. 900 bending angle and 400 bending cycles by showing no considerable change in response even after these extreme bending conditions. The proposed flexible gas sensor remarkable performance to detect ammonia at room temperature indicates its tremendous potential for wearable electronics applications.

Ethylene carbonate generated efficiently via ethylene oxide and CO2 on the Li-MgO(1 0 0) surface based on the synergistic activation of bimetals without halogen

The cycloaddition of ethylene oxide (EO) and CO2 to generate ethylene carbonate (EC) is an atom-efficient process in which halogen-containing catalysts perform admirably. However, the trace halogen frequently remains in EC, making it unsuitable for further use. Exploring a halogen-free catalyst for EC formation is thus an interesting and meaningful work. A gas–solid reaction with magnesium oxide catalyst has been designed and its performance has also been investigated by the density functional theory calculation (DFT). Pure MgO exhibits low activity for the cycloaddition of EO and CO2 due to high activation energy with 278.1 kJ⋅mol−1 to yield EC. A stable Li-MgO catalyst was obtained via ab initio molecular dynamics simulations (AIMD), and various reaction mechanisms were observed. Both Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms for the EC formation exist. However, the most conductive energy path to generate EC is a one-step route via the E-R mechanism with an activation energy of only 39.8 kJ⋅mol−1. And the selectivity of EC can be increased significantly when the temperature exceeds 673 K. Based on the Bader charge and crystal orbital Hamilton populations (COHP) analysis, the bimetals of Li and Mg serve as the active site in Li-MgO catalyst, which replaces the role of halogen in traditional catalysts to activate EO synergistically for generating EC. Furthermore, the prediction of Fourier transform infrared spectroscopy (FTIR) of catalysts can be a valuable reference for the design of green and sustainable catalysts.

Schottky barrier height mediated Ti3C2 MXene based heterostructure for rapid photocatalytic water disinfection: Antibacterial efficiency and reaction mechanism

Schottky barrier plays a key role in determining the interface electron transfer of most Schottky junctions, but the relationship between schottky barrier height (SBH) and photocatalytic disinfection activity is not clearly revealed. Here, a well-designed tubular graphitic carbon nitride/hydroxyl terminated Ti3C2 MXene (TCN/TC(OH)) Schottky junction with controllable SBH was prepared as a model case for investigation. Experimental study and density functional theory calculation confirm that the surface hydroxyl termination of Ti3C2 can lower the SBH of TCN/TC(OH) by reducing its work function (0.23 eV). The lowered SBH ensures rapid interface transfer of photogenerated electron, which decreases the average surface recombination rate from 0.0077 s−1 (TCN/TC) to 0.0045 s−1 (TCN/TC(OH)-3) and increases the corresponding surface charge transfer efficiency from 48.2% to 53.2%. Rotating disk electrode measurement confirms that different from the two-step single-electron O2 reduction of TCN/TC (n = 1.54), TCN/TC(OH)-3 (n = 1.95) exhibits a one-step two-electron reduction route, which is more selective for the generation of the major antibacterial reactive oxygen species H2O2. Consequently, TCN/TC(OH)-3 presents much higher photocatalytic performance towards natural water disinfection, and can entirely inactivate 7 × 107 CFU/mL of Staphylococcus aureus even in complex water matrix (interfering ions, acidic solution and real water samples). Our work provides a feasible guidance for future natural water purification by interfacial engineering of the MXene-based Schottky junction.

Antibacterial Activity and Cell Viability of Biomimetic Magnesian Calcite Coatings on Biodegradable Mg.

Mg is a material of choice for biodegradable implants. The main challenge for using Mg in temporary implants is to provide protective surfaces that mitigate its rapid degradation in biological fluids and also confer sufficient cytocompatibility and bacterial resistance to Mg-coated surfaces. Even though carbonate mineralization is the most important source of biominerals, such as the skeletons and shells of many marine organisms, there has been little success in the controlled growth of carbonate layers by synthetic processes. We present here the formation mechanism, antibacterial activity, and cell viability of magnesian calcite biomimetic coatings grown on biodegradable Mg via a green, one-step route. Cell compatibility assessment showed cell viability higher than 80% after 72 h using fibroblast cells (NCTC, clone L929) and higher than 60% after 72 h using human osteoblast-like cells (SaOS-2); the cells displayed a normal appearance and a density similar to the control sample. Antimicrobial potential evaluation against both Gram-positive (Staphylococcus aureus (ATCC 25923)) and Gram-negative (Pseudomonas aeruginosa (ATCC 27853)) strains demonstrated that the coated samples significantly inhibited bacterial adhesion and biofilm formation compared to the untreated control. Calcite coatings grown on biodegradable Mg by a single coating process showed the necessary properties of cell compatibility and bacterial resistance for application in surface-modified Mg biomaterials for temporary implants.

Fabrication of La, Ce co-doped ZnO nanorods for improving photodegradation of methylene blue

La, Ce co-doped ZnO nanorods (ZnLC) were synthesized through a one-step solvothermal route. The photocatalysts were characterized by X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, energy dispersive X-ray, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. The La and Ce doping enhanced the visible light absorption ability of ZnLC and a red shift was detected for ZnLC. Under simulated solar light irradiation, the ZnO doped with 3 at% La and 1 at% Ce (ZnLC1) degrades methylene blue (MB) more effectively than those of pure ZnO, La-doped ZnO (ZnL) and commercially available ZnO. The improved photocatalytic performance of ZnLC1 can be attributed to the high charge separation efficiency as demonstrated by the photoluminescence spectra. Additionally, the photocatalytic experiments reveal that several parameters have their own impact on the MB degradation. Using a variety of radical scavengers, it is discovered that superoxide anion radical plays a crucial role in the degradation of MB. The ZnLC1 is also reused several times without noticeable decrease of photoactivity, indicating that it has a substantial potential for environmental remediation applications.

Ultrasensitive electrochemical biosensors based on zinc sulfide/graphene hybrid for rapid detection of SARS-CoV-2.

The online version contains supplementary material available at 10.1007/s42114-023-00630-7.

F-doped TiO2(B)/reduced graphene for enhanced capacitive lithium-ion storage

A composite of F-doped TiO2(B) and reduced graphene oxide (F-TiO2(B)/rGO) was successfully synthesized via a one-step hydrothermal route. It was found that the introduction of F ions in the synthetic process has led to the uniform dispersion of TiO2(B) on rGO nanosheets. The F ions have also been doped into the lattice of TiO2(B), which greatly improved the conductivity of the materials. Consequently, this composite delivered a large capacity of 249.4 mA h g−1 at 0.2 A/g. It also demonstrated a capacity of 203.1 mA h g−1 and an excellent capacity retention of 96% after 500 cycles even at a high current density of 2 A/g.

Molten-salt confined synthesis of nitrogen-doped carbon nanosheets supported Co3O4 nanoparticles as a superior oxygen electrocatalyst for rechargeable Zn-air battery

Rational design and preparation of high-efficiency oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts is crucial for the large-scale practical application of rechargeable Zn-air batteries. In this work, employing a combined strategy of self-sacrificial template and molten-salt confinement effect, a facile one-step pyrolysis route has been developed to synthesize defect-rich N-doped carbon nanosheets supported Co3O4 nanoparticles (Co3O4@NCNs). The pyrolytic precursor is built up of NaCl encapsulated ZnO@zeolitic imidazolate framework-67 core-shell particles. Thanks to the pore-forming and oxygen source functions of ZnO and the confinement effect of NaCl, the holed NCNs in Co3O4@NCNs are interconnected into a 3D porous carbon structure with a high N-dopant level. The as-prepared Co3O4@NCNs catalyst exhibits excellent bifunctional ORR/OER electrocatalytic activities with a half-wave ORR potential (E1/2) of 0.84 V, an ultralow gap of 0.63 V between OER Ej = 10 mA/cm2 and ORR E1/2 potentials, and prominent long-term durability. Its rechargeable Zn-air battery displays a high power density up to 173.8 mW cm−2 and superior cycling stability. This work highlights a novel strategy for the component and architecture design of high-performance carbon-based electrocatalysts in energy conversion and storage systems.

Preparations of antibacterial yellow-green-fluorescent carbon dots and carbon dots-lysozyme complex and their applications in bacterial imaging and bacteria/biofilm inhibition/clearance

The preparation of functional long-wavelength-emitting nanomaterials and the researches on their applications in antibacterial and antibiofilm fields have important significance. This paper reports the preparation of yellow-green-fluorescent and high- quantum yield carbon dots (4-ACDs) with 4-aminosalicylic acid and polyethylene imine as raw materials through one-step route, and the impacts of raw material structure and the reaction conditions upon the optical properties of the products have been investigated. 4-ACDs exhibit excellent broad-spectrum antibacterial activity, and their good biocompatibility ensures them as ideal fluorescent nano-probe for cell imaging. However, 4-ACDs could not effectively eliminate the biofilm of Staphylococcus aureus (S. aureus). CDs-LZM complex was prepared through the coupling between 4-ACDs and lysozyme (LZM) and the complex showed strong antibacterial activity against Gram-positive bacteria, particularly with MIC against S. aureus at 5 μg mL−1. Besides, CDs-LZM showed excellent ability against the biofilm of S. aureus. At the concentration of 60 μg mL−1, its inhibition rate against the growth of biofilm was 86 %, and elimination rate against biofilm reached 76 %. CDs-LZM exhibited obvious antibiofilm ability through removing extracellular matrix of biofilm, greatly reducing the thickness of biofilm under confocal microscopy. The application of novel long-wavelength-emitting nanomaterial in eliminating pathogenic bacteria is of great significance.

Plastic-derived sandwich-like porous carbon nanosheet-supported hexagonal carbon micro-flakes for K-ion storage.

Novel sandwich-like porous carbon nanosheet-supported hexagonal carbon micro-flakes (WPWMC) are fabricated via a one-step hydrothermal route at 700 °C with polyethylene as the precursor and magnesium as the inducer. Through various characterizations, it is confirmed that the hexagonal carbon micro-flakes exhibit (002) orientation, which exposes abundant edge active sites and shortens the K+ transmission path. Moreover, the inside cross-linked carbon nanosheets with abundant pores can accelerate ion diffusion and increase the capacitive contribution. The WPWMC anode displays a high reversible capacity (528.7 mA h g-1 at 0.2 A g-1), good rate capability (152.7 mA h g-1 at 10 A g-1) and long-term cycle stability (112.1 mA h g-1 at 5 A g-1 after 10 000 cycles). Furthermore, the WPWMC//CMK-3 hybrid capacitor exhibits an energy density of 222.7 W h kg-1 at 446.2 W kg-1. This work provides an idea for transforming waste plastic into value-added materials.

3D nanostructured Ce-doped CoFe-LDH/NF self-supported catalyst for high-performance OER.

Powder electrocatalysts for oxygen evolution reactions usually need adhesives for electrocatalytic performance tests, leading to the increase of resistance, reduction of catalyst loading, and easy stripping of the catalyst under long-time or high current operation. In this study, Ce-doped CoFe layered double hydroxides were uniformly grown on nickel foam by a one-step hydrothermal route. A nanostructured self-supported electrode Ce-CoFe-LDH/NF without adhesive was obtained directly, which has a regular nanoneedle morphology with a length of ∼1.2 μm and tip width of ∼20 nm. Adopting Ce3+ ions with a large radius to partially displace Fe3+ ions with a small radius produced lattice distortion and more defects in the host layer of CoFe-LDH, whereby possessing the great potential to enhance catalytic behaviors. Once used as an electrocatalyst for the oxygen evolution reaction, Ce-CoFe-LDH/NF shows an outstanding electrocatalytic performance, including an optimized overpotential of 225 mV at 10 mA cm-2, a decreased Tafel slope of 34.34 mV dec-1, and a low charge transfer impedance of 2.4 Ω in 1 M KOH electrolyte. Moreover, the overpotential of the working electrode increased by only 0.04 V after 24 hours and was maintained at a current density of 50 mA cm-2. These results demonstrate a low-cost strategy compared to using noble metal OER electrocatalysts. Thus, this study highlights a ready universal approach to fabricate high-performance supported catalysts for energy-related applications.

Constructing a mesoporous carbon incorporated FeF3 nanocomposite cathode by one-step impregnation route for Li-ion battery applications

Mesoporous carbon incorporated FeF3 nanocomposite could serve as potential candidate for energy storage cathode material in Li-ion battery applications.