Rod-like Nanostructures Research Articles

Regulation of Ni3S2@NiS Heterostructure Grown on Industrial Nickel Net for Improved Electrocatalytic Hydrogen Evolution

A novel all-in-one catalytic electrode containing a Ni3S2@NiS heterostructure (Ni3S2@NiS/Ni-Net) was in situ synthesized on an industrial nickel net (Ni-Net) using a one-step solvothermal method, in which ethanol was the solvent and thioacetamide was the sulfur source, respectively. The effects of the addition amount of the sulfur source on the composition, morphology, and electronic structure of the Ni3S2@NiS heterostructures and their electrocatalytic hydrogen evolution reaction (HER) activities were investigated. When 2 mmol of sulfur source was introduced, the prepared Ni3S2@NiS/Ni-Net electrode with a nanorod-like structure required overpotentials of 207 and 322 mV to drive the current densities of 100 and 500 mA/cm2, respectively, in 1 M KOH solution, and only needed the overpotential of 429 mV to deliver 1000 mA/cm2. Meanwhile, the Ni3S2@NiS/Ni-Net electrode can operate stably at a high current density of 90 mA/cm2 under harsh alkaline conditions for at least 100 h. The results show that the Ni3S2@NiS/Ni-Net electrode has high activity and stable HER performance at a high current density, which provides a new idea for the development of high-efficiency electrodes for industrial alkaline hydrogen production.

Morphology Transition of Tripeptides from Porous Spherical to Rod-like Nanostructures for Small-Molecule Adsorption.

Peptides possess a remarkable propensity to adopt distinct morphologies, ranging from simple aggregates to complex structures such as fibrils and nanotubes. Morphology transformation in peptides is intricately linked to the physicochemical properties of peptides and external factors such as pH, temperature, and solvent conditions. Thus, it is more complex. Herein, we present four tripeptides, Boc-LVL-OMe (LVL), Boc-IVI-OMe (IVI), Boc-LVI-OMe (LVI), and Boc-IVL-OMe (IVL), which undergo direct morphological transformation (except for Boc-IVL-OMe) with time. The morphological transformation from nanospheres to rod-like structures was verified using electron microscopic studies (FESEM and FETEM). Dynamic light scattering (DLS) studies further supported the results and are in good agreement with the observed phenomena. CD and FTIR studies were conducted for conformational analysis, suggesting a mixture of unordered and β-sheet conformations. Except for IVL, all other tripeptides are mesoporous and adsorb N2 gas. Another important application of our designed tripeptides is that they can encapsulate the low-molecular-weight biologically active drug molecule curcumin. The encapsulation property and its sustained release after being treated with salt were studied by using fluorescence spectroscopy and fluorescence microscopy. Therefore, understanding the dynamics of these interactions and their impact on peptide morphology is crucial for harnessing their functional diversity in applications, such as drug delivery, tissue engineering, and nanotechnology.

Boosting the optoelectronic properties of V2O5 thin films by Fe3+ doping for photodetector applications

Prevailing the demands of UV optoelectronics gadgets with improved efficiency and low-cost fabrication in this commercial and competitive world, we at this moment report an improved photo response capabilities of V2O5 thin films by incorporating Fe content of (0, 1, 2, 3, 4 and 5 wt%) over the glass substrates using nebulizer assisted spray pyrolysis technique. The X-ray diffraction (XRD) analysis authenticates the existence of an orthorhombic crystal structure with an intense peak along (010) plane. The FESEM reveals the morphology of tubular nano rod-like structures with a porous nature for all the V2O5 samples. The presence of compositional elements in the samples was evident by EDX analysis. UV spectral studies show that the bandgap varies from 2.41 eV to 2.1 eV. The PL spectra exemplify the existence of violet emission at 475 nm. The performance of the UV photodetector was analyzed in terms of parameters like Responsivity, Detectivity and External Quantum Efficiency and is observed to be maximum for 3 % Fe doped V2O5 (R = 46.4 × 10−2AW−1, D∗ = 4.26 × 1010Jones and EQE = 150 %).

Controlled nanorod-like structure of iron tetrapolyvanadate for enhanced heterogeneous Fenton-like catalysis

Controlled nanorod-like structure of iron tetrapolyvanadate for enhanced heterogeneous Fenton-like catalysis

Eco-Friendly Synthesis of ZnO for Efficient Photodegradation of Pharmaceutical Drug Removal by Photocatalysis.

In the present work, a comparative study on eco-friendly synthesis of zinc oxide (ZnO) sample 1 and sample 2 with 3.17 and 4.17 M NaOH, respectively, is reported. Sample 2 with 4.17 M NaOH is applied in the photocatalytic degradation of paracetamol (pure and raw both) using the ultraviolet (UV, 280-400 nm) and UV/H2O2 reaction systems. Pure paracetamol (PCM1) and raw paracetamol (PCM2) from tablets are used for photocatalytic degradation by photocatalysis. Our experimental evidence show that ZnO sample 2 was more active in the UV/H2O2 reaction system than under ultraviolet (UV, 280-400 nm) irradiation only in the photocatalytic degradation process. Field emission scanning electron microscopy (FE-SEM) confirms the homogeneous growth of a rod-like structure for sample 1 and brittle and randomly aggregated rod-like and wire-like nanostructures for sample 2. The peaks observed in the region around 440 to 900 cm-1 in the FTIR spectra for sample 1 and sample 2 annealed at 250 °C confirms the presence of ZnO bonds. UV absorption spectroscopy indicates a red shift in the absorption spectra due to the increase in the molar concentration of NaOH to 4.17 M for sample 2. In this study, the band gap values are found to be 3.33 and 3.01 eV for the synthesized ZnO sample 1 and sample 2, respectively, which are 40 and 360 meV less as compared to that of bulk ZnO (3.37 eV). The oxidation rate is increased in the UV/H2O2 reaction system, producing the highest rate for PCM1 drug removal with rate constant 9.7 × 10-3 min-1 and half-life 71.5 min. The kinetic study results for the removal of PCM1 and PCM2 show good results and follow the pseudo-first-order kinetic model with correlation coefficients 0.69556 and 0.90851, respectively, whereas PCM2 follows the pseudo-second-order kinetic model with correlation coefficient 0.9993. The experimental and calculated values of removal capacity (q e) at equilibrium is found close to those of the pseudo-second order kinetic model for the removal of both the paracetamol forms PCM1 and PCM2 with the catalyst ZnO nanostructure. The photostability of ZnO sample 2 is also tested with a reusability test in photocatalytic degradation of paracetamol at least four times. The absence of a maxima peak at 243 of PCM1 in the UV/H2O2 reaction system indicates nearly 100% successful conversion of 20 ppm PCM1 by using synthesized catalyst ZnO sample 2. The comparative results of both reaction systems, i.e., UV and UV/H2O2, show that the hydroxyl radicals, as the active species, are responsible for major degradation of both paracetamol forms (PCM1 and PCM2).

Assessment of silver and graphitic carbon nitride doped cadmium selenide quantum dots as an efficient dye degrader and antibacterial agent: In silico molecular docking analysis

This study demonstrates the synthesis of co-precipitated cadmium selenide (CdSe) quantum dots (QDs) doped with (2 and 4 wt %) of silver (Ag) and fixed quantity of graphitic carbon nitride (g-C3N4) for catalytic as well as antibacterial potential with molecular docking (MD) analysis. Comprehensive characterizations investigated the structural composition, surface morphology, elemental composition, and optical properties. XRD revealed the multiple phases (hexagonal and cubic) of CdSe with a notable rise in the diffraction peaks intensity upon doping. The optical studies demonstrated the range of absorption peaks, which increased upon doping confirmed through band gap energies significantly altered. TEM study revealed that a sheet of g-C3N4 overlapped with CdSe QDs, and certain nanorod-like structures emerged after Ag doping. HR-TEM was employed for the d-spacing computation of prepared samples and exposed a decreasing trend as the Ag concentration increased. Furthermore, the catalytic activity (CA) performed against RhB dye showed maximum results in the acidic medium with a higher concentration of Ag into g-C3N4 doped CdSe. The efficient bactericidal efficacy was evaluated against S. aureus bacteria with the highest inhibition zone of 13.75 mm for 4% Ag doping, which was further explained by investigating their inhibitory effects on DNA gyrase and tyrosyl-tRNA synthetase via MD.

Bottom-up synthesis of novel cesium ferrate (Cs2FeO4) nanorods: Tailoring the structural and optical characteristics with room-temperature ferromagnetic and colossal dielectric performance

This paper presents a detailed protocol for the synthesis and characterization of cesium ferrate nanorods, a unique material that possesses a wide range of functionalities. These include the ability to demonstrate ferromagnetism at normal ambient temperature and the capacity to modify its structural, optical, and electrical properties. The XRD patterns specify the presence of an orthorhombic alkali ferrate phase (Cs2FeO4), with the size of the crystals increasing as the temperature rises. Furthermore, the XPS spectra of Cs 3d, Fe 2p, and O 1 s exhibit the formation of substances due to the peak positions fluctuate in reaction to temperature variations. The nanorod-like structure and size distribution of materials can be visualized using TEM and SEM. The UV spectra of the samples indicate broad absorption bands ranging from the visible to the near infrared (IR) region. Calcination of the as-prepared Cs2FeO4 at 400 and 600 ºC lowered the optical band gap from 2.15 to 2.04 and 2.06 eV, respectively. The temperature's synergistic effect is crucial in transforming materials from a paramagnetic to a ferromagnetic phase. The colossal sample's dielectric constant, which varies from around 107 at 600 ºC to 106 and 105 in the lower frequency band, and electrical conductivity show substantial fluctuations depending on the frequency. Nanorod systems have interesting optical, dielectric, and ferromagnetic properties at room temperature that could be used in many areas, such as photocatalysis, energy storage, and spintronics.

Design and construction of V6O13/C nanorods as high-performance cathode material for aqueous zinc-ion batteries

As a candidate for commercial cathode material of aqueous zinc ion batteries (AZIBs), vanadium-based materials have attracted wide attention due to their unique layered structure and high specific capacity. However, the insertion/extraction process of Zn2+ can easily lead to the volume expansion of vanadium-based materials, resulting in battery failure. In addition, the inherent low conductivity and low diffusion kinetics of vanadium-based materials limiting their further development into high-performance cathode materials. Herein, a novel V6O13/N, O co-doped carbon (V6O13/C) nanorod electrode material has been successfully fabricated as a cathode for AZIBs. The N, O co-doped carbon can significantly improve the conductivity of materials and alleviate the volume change. The nanorod-like structure could enhance the structural stability during the Zn2+ insertion/extraction processes. Moreover, with N, O doped, the electrode can expose more reactive sites which is beneficial for promoting electrochemical processes. With the synergistic effort of the above optimization strategy, the as-obtained electrode delivers excellent long-term cycle stability of 151.7 mAh g−1 at 1 A g−1 after 1000 cycles.

Characterization of WO3/Silicone Rubber Composites for Hydrogen-Sensitive Gasochromic Application.

WO3 and silicone rubber (SR)-based gasochromic composites were fabricated to detect hydrogen leaks at room temperature. WO3 rod-like nanostructures were uniformly distributed in the SR matrix, with a particle size of 60-100 nm. The hydrogen permeability of these composites reached 1.77 cm3·cm/cm2·s·cmHg. At a 10% hydrogen concentration, the visible light reflectance of the composite decreased 49% during about 40 s, with a color change rate of 6.4% s-1. Moreover, the composite detected hydrogen concentrations as low as 0.1%. And a color scale was obtained for easily assessing hydrogen concentrations in the environment based on the color of composites. Finally, the composite materials as disposable sensors underwent testing at several Sinopec hydrogen refueling stations.

Welded Gold Nanoparticle Assemblies Defined Plasmonic Coupling.

Nanoparticle assemblies with interparticle ohmic contacts are crucial for nanodevice fabrication. Despite tremendous progress in DNA-programmable nanoparticle assemblies, seamlessly welding discrete components into welded continuous three-dimensional (3D) configurations remains challenging. Here, we introduce a single-stranded DNA-encoded strategy to customize welded metal nanostructures with tunable morphologies and plasmonic properties. We demonstrate the precise welding of gold nanoparticle assemblies into continuous metal nanostructures with interparticle ohmic contacts through chemical welding in solution. We find that the welded gold nanoparticle assemblies show a consistent morphology with welded efficiency over 90%, such as the rod-like, triangular, and tetrahedral metal nanostructures. Next, we show the versatility of this strategy by welding gold nanoparticle assemblies of varied sizes and shapes. Furthermore, the experiment and simulation show that the welded gold nanoparticle assemblies exhibit defined plasmonic coupling. This single-stranded DNA encoded welding system may provide a new route for accurately building functional plasmonic nanomaterials and devices.

انماء تراكيب نانوية من أكسيد الزنك بطريقة التحلل المائي الحراري لقيم مختلفة من درجة الحامضية

تم تحضير تراكيب نانوية (زهرية وعصي) الشكل من اكسيد الزنك بالطريقة الحرارية المائية عند 90 درجة مئوية لمدة ثلاث ساعات. تم تحضير ثلاثة محاليل بقيم درجة الحامضية 9 و10 و11 وبمولارية 0.028 مولاري، على قواعد زجاجية / بذور ZnO. كان لجميع العينات المحضرة نمط حيود متعدد التبلور مع حيود سائد من المستوى (002). مع زيادة درجة الحامضية، زاد حجم البلوري إلى حد أقصى قدره 37.6 نانومتر. أظهرت صور الانبعاث الحقلي لمجهر الماسح الإلكتروني تكمن اهمية البحث في انماء تراكيب مختلفة من اكسيد الزنك من خلال التحكم بدرجة الحامضية حيث أظهرت النتائج ظهور تراكيب زهرية عند الحامضية 11 وبحجم جسيمي 100-800 نانومتر، وانماء تراكيب نانوية بشكل حزمة من العصي عند الحامضية 10 وبحجم جسيمي 500-800 نانومتر وانماء اكسيد الزنك بشكل عصي منفردة عمودية على السطح عند الدرجة الحامضية 9 وبحجم حبيبي 70-80 نانومتر. أظهرت الخصائص البصرية انخفاضًا في النفاذية من 78.75 الى 79.32 وزيادة في قيم فجوة الطاقة من 3.18 الكترون فولط الى 3.31 الكترون فولط مع زيادة درجة الحامضية.

Unveiling the impact of Fe-doping concentration on the local structure and morphological evolution of Cr2O3 nanoparticles

A series of Cr2−xFexO3 (0.0 ≤ x ≤ 0.3) nanoparticles were successfully synthesized using a sol-gel-based method. Analysis through XRD and SAED of both pure and Fe-doped Cr2O3 nanoparticles revealed a rhombohedral structure belonging to the R3‾cD3d6 space group, without the formation of secondary phases or Fe clusters. Fe ions were well integrated, as indicated by fluctuations in lattice parameters, and lattice strain. The crystallite size decreased from 38.42 to 27.54 nm with increasing doping concentration. HRTEM images depicted evenly distributed nanoparticles. At lower dopant concentrations (x = 0.1), smaller and more heterogeneous nanorod-like structures emerged, with average sizes and lengths of 36.56 and 39 nm, respectively. Increasing the doping content to x = 0.2 resulted in a morphological shift towards semi-spherical and ellipsoidal shapes, with average dimensions of 22.84 and 31 nm, respectively. At higher doping levels (x = 0.3), nanoparticles grew to 66.5 nm in size and exhibited a spherical morphology. Raman and Fourier transform infrared spectra showed red-shifting of absorption bands with increasing Fe content, attributed to variations in bond length and Cr/Fe–O–Cr/Fe structural perturbation. XPS and Mössbauer spectroscopy analyses confirmed the oxidation states of Fe3+ and ionized oxygen vacancies in the crystal lattice of Cr2O3 nanoparticles. Higher values of quadrupolar splitting Δ indicated greater structural disorder induced by Fe3+ in octahedral positions and in an oxygen-deficient environment. Atomistic simulations confirmed that Fe3+ dopants can induce the presence of vacancy-complexes, forming a stable double-defect configuration with vacant Cr sites along the c-axis, proximal to oxygen vacancies with a single positive charge. These findings offer both experimental and theoretical insights into the dynamics of structural defects in trivalent transition metal doping of Cr2O3 nanoparticles, which holds significant implications for spintronics research.

Nitrogen assisted one-step hydrothermal synthesis of commercial TiO2 for methylene blue degradation under visible light irradiation

Strategies to make more efficient use of sunlight have been developed. Different synthesis parameters have been studied for the production of multiphase photocatalysts. In this work, for the first time, the performance of a one-step nitrogen-assisted hydrothermal synthesis of TiO2 using TiO2–P25 as a Ti precursor was investigated for the degradation of methylene blue under visible light irradiation. Urea and ethylenediamine (EDA) were evaluated as nitrogen sources. The produced photocatalysts had a rod-like nanostructure with the formation of mesopores. The resulting phase was a heterojunction of anatase, TiO2(B), and rutile, which enhanced charge separation. The presence of nitrogen during the hydrothermal reaction altered the morphology of TiO2, impacting the crystallite size. The U photocatalyst (urea source) achieved the best result for visible light with prior adsorption, degrading around 11 % of methylene blue in 5 h. This shows that it is possible to obtain a photocatalyst with superior performance to TiO2–P25 under both ultraviolet and visible light. This study presents an efficient strategy for improving the optical response of TiO2 by using nitrogen during a hydrothermal reaction, which has potential for industrial applications.

Control of Kinetic Pathways toward Supramolecular Chiral Polymorphs for Tunable Circularly Polarized Luminescence.

An amphiphilic aza-BODIPY dye (S)-1 bearing two chiral hydrophilic side chains with S-stereogenic centers was synthesized. This dye exhibited kinetic-controlled self-assembly pathways and supramolecular chiral polymorphism properties in MeOH/H2O (9/1, v/v) mixed solvent. The (S)-1 monomers first aggregated into a kinetic controlled, off-pathway species Agg. A, which was spontaneously transformed into an on-pathway metastable aggregate (Agg. B) and subsequently into the thermodynamic Agg. C. The three aggregate polymorphs of dye (S)-1 displayed distinct optical properties and nanomorphologies. In particular, chiral J-aggregation characteristics were observed for both Agg. B and Agg. C, such as Davydov-split absorption bands (Agg. B), extremely sharp and intense J-band with large bathochromic shift (Agg. C), non-diminished fluorescence upon aggregation, as well as strong bisignated Cotton effects. Moreover, the AFM and TEM studies revealed that Agg. A had the morphology of nanoparticle while fibril or rod-like helical nanostructures with left-handedness were observed respectively for Agg. B and Agg. C. By controlling the kinetic transformation process from Agg. B to Agg. C, thin films consisting of Agg. B and Agg. C with different ratios were prepared, which displayed tunable CPL with emission maxima at 788-805 nm and g-factors between -4.2×10-2 and -5.1×10-2.

Platinum-Modified Rod-like Titania Mesocrystals with Enhanced Photocatalytic Activity

Photocatalysis is considered as an environmentally friendly method for both solar energy conversion and environmental purification of water, wastewater, air, and surfaces. Among various photocatalytic materials, titania is still the most widely investigated and applied, but more efforts must be carried out considering the synthesis of highly efficient photocatalysts for multifarious applications. It is thought that nanoengineering design of titania morphology might be the best solution. Accordingly, here, titania mesocrystals, assembled from crystallographically oriented nanocrystals, have been synthesized by an easy, cheap, and “green” solvothermal method (without the use of surfactants and templates), followed by simple annealing. The obtained materials have been characterized by various methods, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and diffuse reflectance spectroscopy (DRS). It has been found that the as-obtained photocatalysts exhibit a unique nanorod-like subunit structure with excellent crystalline and surface properties. However, pristine titania is hardly active for a hydrogen evolution reaction, and thus additional modification has been performed by platinum photodeposition (and silver as a reference). Indeed, the modification with only 2 wt% of noble metals results in a significant enhancement in activity, i.e., ca. 75 and 550 times by silver- and platinum-modified samples, respectively, reaching the corresponding reaction rates of 37 μmol h−1 and 276 μmol h−1. Additionally, titania mesocrystals exhibit high oxidation power under simulated solar light irradiation for the degradation of antibiotics within the tetracycline group (tetracycline (TC), ciprofloxacin (CIP), norfloxacin (NOR) and oxytetracycline hydrochloride (OTC)). It has been found that both experimental results and the density functional theory (DFT) calculations confirm the high ability of titania mesocrystals for oxidative decomposition of tetracycline antibiotics.

Nanorod-like Bimetallic Oxide for Enhancing the Performance of Supercapacitor Electrodes.

Supercapacitors are widely used in many fields owing to their advantages, such as high power, good cycle performance, and fast charging speed. Among the many metal-oxide cathode materials reported for supercapacitors, NiMoO4 is currently the most promising electrode material for high-specific-energy supercapacitors. We have employed a rational design approach to create a nanorod-like NiMoO4 structure, which serves as a conductive scaffold for supercapacitors; the straightforward layout has led to outstanding results, with nanorod-shaped NiMoO4 exhibiting a remarkable capacity of 424.8 F g-1 at 1 A g-1 and an impressive stability of 80.2% capacity preservation even after 3500 cycles, which surpasses those of the majority of previously reported NiMoO4 materials. NiMoO4//AC supercapacitors demonstrate a remarkable energy density of 46.31 W h kg-1 and a power density of 0.75 kW kg-1. This synthesis strategy provides a facile method for the fabrication of bimetallic oxide materials for high-performance supercapacitors.

Fabrication and characterization of solar active BN coupled with ZnO composite catalysts for efficient photocatalytic detoxification of methyl orange dye under solar and visible light irradiation

In this paper, pure ZnO and hexagonal boron nitride (BN) loaded ZnO nanorods were synthesized via a simple hydrothermal method. XRD analysis revealed good crystallinity and hexagonal wurtzite structure of the synthesized materials. FE-SEM images showed the nanorod-like structure of the ZnO material. The UV-DRS spectra showed a decrease in the optical bandgap of BN-ZnO due to the loading of BN. The outcomes from the EIS analysis indicated that the 3% BN-ZnO photocatalyst exhibited the most favorable recombination rate for electron-hole pairs and the least resistance to electron transfer. Photocatalytic evaluation for methyl orange (MO) detoxification under sunlight and visible light illumination revealed that 3% BN-ZnO showed the highest activity, and kinetic studies showed pseudo-first-order degradation. Moreover, the sunlight process outperforms than visible light process, which can be attributed to the ≈ 4% UV radiation available in the solar spectrum. TOC studies confirmed the mineralization of the MO dye. Trapping experiments using various quenchers show that superoxide radicals (O2•−) anion play a major role in the degradation process. Finally, we proposed a plausible photocatalytic mechanism based on our findings.

Yttrium doping improves stability of manganese dioxide cathode for aqueous zinc ion batteries

Manganese-based oxides are a promising cathode material for aqueous zinc ion batteries. However, structural change and irreversible dissolution of manganese in manganese-based oxides during charging and discharging lead to poor cycling stability, which hinders their large-scale application. Elemental doping is an effective way to regulate the bonding strength and crystal structure of the material. In this paper, YMO materials with nanorod-like structures have been obtained by a hydrothermal method. Y-element doping enhances the stability of the material and improves the electronic and ionic conductivity of the material. The YMO material exhibits excellent electrochemical performance as a cathode material for aqueous zinc ion batteries. The electrode exhibits a high reversible discharge specific capacity of 409.3 mAh g−1 at a current density of 0.1 A g−1, and the electrode capacity hardly decays after 100 charge/discharge cycles, meanwhile, the YMO electrode shows good initial cycling stability even at different charge/discharge current densities. In addition, the YMO electrodes showed long-term cycling stability, with a capacity retention rate of 95.1% after 2000 cycles at a current density of 1 A g−1. The excellent cycling stability of the electrode is mainly due to the improved structural stability of YMO, which is related to the stronger YO bonds acting as anchors in the lattice structure of MnO2. Meanwhile, the strong interaction between doped Y3+ and O2− promotes the storage of H+. Structurally stable electrode materials obtained by optimizing doping elements to modulate bonding energy is an effective way to improve the stability of manganese-based materials.

Hydrothermal transforming phase structure and chemical composition of V2O5 for elevating electrochemical property of zinc ion batteries

V2O5 was hydrothermally modified in NaOH or KOH solutions at 180 °C for 24 h. The NaOH-modified powders had a nanorod-like structure with a crystal structure matching Na2V6O16·nH2O. The TG/DTA results of Na2V6O16·nH2O powders show a mass reduction of 4.24 % at 300 °C, corresponding to n of 1.496. KOH-modified powders have large rods and irregular structures with a crystal structure matching KV3O8. Its TG/DTA spectrum shows a very small percentage change, just 0.37 % at 600 °C. Cyclic voltammetry (CV) curves of a Na2V6O16·nH2O cathode in a 2 M ZnSO4 electrolyte exhibit higher oxidation and reduction current densities than those of pure V2O5 and KV3O8 electrodes.The best capacity of a Na2V6O16·nH2O electrode is 296.10 mAh g-1 at a current density of 50 mA g−1, which is higher than those of pure V2O5 (102.90 mAh g-1) and KV3O8 (91.07 mAh g-1) electrodes. EDS and XPS results reveal that the charge and discharge states involve de-insertion and insertion of Zn2+ ions out of/into the electrodes. Computational analysis of Zn intercalation into V2O5, Na2V6O16·nH2O, and KV3O8 structures displays increasing electron density on neighboring V atoms, which explains the increasing V4+/V5+ ratio in the discharged state as evidenced by XPS spectra.

Synergistic effect of bimetallic NiCo-MOF on foamed nickel for application in high-performance supercapacitors

In this study, a series of bimetallic NiCo-MOFs with nanorod-like structures were successfully prepared on a foamed nickel skeleton.