Nickel Nanowires Research Articles

Significant magnon contribution to heat transfer in nickel nanowires

Magnons, quantized spin waves arising from collective excitations of spins, are typically considered negligible contributors to heat transfer. However, recent studies on low-dimensional magnetic materials have challenged this notion, revealing significant magnon-mediated heat transport. The underlying physics behind this phenomenon, however, remains poorly understood. In this study, we observed a significant reduction in heat transfer in nickel nanowires under the influence of a magnetic field. Our theoretical model revealed a substantial magnon contribution of up to 30 % to nanowire heat transfer. The reduction in heat transfer under a magnetic field stemmed from a drastic decrease in the magnon mean free path (MFP). This decrease in MFP was primarily attributed to suppressing long wavelength magnons with a longer MFP. Our findings provide deeper insights into heat transfer mechanisms in nanoscale ferromagnetic materials and offer valuable guidance for the design of future spintronic devices.

High-performance honeycomb porous microwave absorbers: Gelatin-based carbon nanotube/nickel nanowire aerogels

Biomass-derived carbon absorbent materials have received significant attention due to their renewability, diverse sources, and ease of preparation. In this work, a honeycomb porous electromagnetic wave absorber with excellent performance was successfully prepared by blending gelatin and multi-walled carbon nanotubes (MWCNTs), followed by freeze-drying. Metallic nickel nanowires (NiNWs) were then introduced as a second phase using an in-situ growth method. The minimum reflection loss (RL) of the aerogel containing 8.06 wt% MWCNTs and 3.36 wt% NiNWs was −36.1 dB at a thickness of 3.1 mm, with the effective absorption bandwidth (EAB) covering the entire X-band. Additionally, the aerogel exhibited a very low density (36 mg/cm3) and remarkable strength, capable of supporting over 1658 times its weight for more than 24 h without deformation. These properties make it highly valuable for commercial use and provide new inspiration for the future development of biomass carbon-based electromagnetic absorbing materials.

ZnS-zeolitic imidazolate framework nanostructure anchored on Ni nanowires as a bifunctional electrocatalyst for high-efficiency overall water splitting

The design and construction of stable and inexpensive bifunctional catalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) present a challenge in electrocatalytic water splitting. In this study, we utilized zeolitic imidazolate frameworks-8 (ZIF-8) as the precursor to fabricate ZnS-ZIF-8 via facile sulfidation processes. The ZnS-ZIF-8 nanostructures were anchored on the surface of the nickel nanowire (denoted as Ni NWs@ ZnS-ZIF-8 nanocomposite) and their catalytic activity for HER, OER, and overall water splitting were studied. The prepared Ni NWs@ ZnS-ZIF-8 revealed a low overpotentials value of 90 and 260 mV at 10 mA cm−2 for HER and OER in 1.0 M KOH solution, respectively. The alkaline electrolyzer assembled by Ni NWs@ ZnS-ZIF-8 provides a low cell voltage of 1.61 V at 10 mA cm−2 current density to boost the overall water splitting and robust stability for 15 h. The superior electrocatalytic activity of Ni NWs@ ZnS-ZIF-8 is owing to the facile and effective electron transport of Ni NWs, accessible active sites of ZnS-ZIF-8, and as well as the synergistic effect of the nanocomposite structures. This finding presents a viable methodology for synthesizing a proficient noble-metal-free catalyst for energy conversion and storage.

Surface fluorination of nickel nanowires enabling LiF-rich nanoscale solid electrolyte interface for stable lithium anodes

Lithium (Li) metal has become a research hotspot for anodes materials due to its ultra-high theoretical capacity and the lowest redox potential. However, the practical application of Li metal batteries is hampered by the formation of uncontrollable Li dendrites and the irreversible structural changes during long-term charge/discharge processes. Developing stable Li metal anode with uniform Li deposition is highly desirable. Herein, surface fluorination of nickel nanowires enabling LiF-rich nanoscale solid electrolyte interface was demonstrated for stable Li anodes. Free-standing three-dimensional (3D) nickel nanowires (NiNWs) current collector decorated with lithiophilic NiF2 nanosheets (NiNWs@NiF2) was constructed via a simple and scalable fluorination strategy. Theoretical and experimental analysis confirmed that the lithiophilic surface of NiF2 nanosheets could reduce the Li nucleation barrier, facilitating uniform Li ion deposition. The 3D conductive NiNWs network enabled fast electron transfer and mitigated volume changes during cycling. Additionally, a LiF-rich nanoscale solid electrolyte interface (SEI) layer formed between Li and the electrolyte significantly improved the interfacial stability. As a result, the as-assembled Li-NiNWs@NiF2 symmetrical cell provided a superior electrochemical performance, maintaining stability for 2500 h at 1.0 mA cm−2 and 900 h at 5.0 mA cm−2. Furthermore, the assembled Li-NiNWs@NiF2|| LiFePO4 (LFP) full cell demonstrated exceptional capacity retention of 93.9 % after 2000 cycles at a rate of 5C. Overall, the unique structure of NiNWs@NiF2 not only offers a straightforward method for designing a 3D lithiophilic host, but also provides the concept of interfacial engineering through the in-situ construction of an artificial LiF-rich nanoscale SEI layer.

Multifunctional Conductive Hydrogel Composites with Nickel Nanowires and Liquid Metal Conductive Highways.

The dramatic growth of smart wearable electronics has generated a demand for conductive hydrogels due to their tunability, stimulus responsiveness, and multimodal sensing capabilities. However, the substantial trade-off between mechanical and electrical properties hinders their multifunctionality. Here, we report a double-network hydrogel composite that features a conductive "highway" constructed using magnetic-field-aligned nickel nanowires and liquid metal. The liquid metal fills the gaps between the aligned nickel nanowires. Such interconnected structures can form efficient conductive paths at low filler content, resulting in high conductivity (1.11 × 104 S/m) and mechanical compliance (Young's modulus, 89 kPa; toughness, 721 kJ/m3). When used as a wearable sensor, the hydrogel displays a high sensitivity and fast response for wireless motion detection and human-machine interaction. Furthermore, by exploiting its outstanding conductivity and electrical heating capacity, the hydrogel integrates electromagnetic shielding and thermal management functionalities. Owing to these all-around properties, our design offers a broader platform for expanding hydrogel applications.

CoFe2O4 nanosheets grown in situ on nickel nanowires for efficient hydrazine oxidation-boosted hydrogen production

The use of the hydrazine oxidation reaction (HzOR) to replace the oxygen evolution reaction (OER), which has a large thermodynamic barrier and a slow kinetic process, is a feasible way to achieve energy saving hydrogen production, but the construction of superior bifunctional catalysts is also challenging. Herein, an array (CoFe2O4@NNWs) of CoFe2O4 nanosheet grown in situ on nickel nanowires (NNWs) has been prepared and showed the excellent performance for hydrogen evolution reaction (HER) and HzOR under alkaline media, which require a lower potential of −91 mV (vs. RHE) for HzOR and 45 mV (vs. RHE) for HER at the current density (j, 10 mA cm−2). The overall hydrazine splitting (OHzS) electrolyzer requires cell voltages of 0.028 V (10 mA cm−2) and 1.227 V (1000 mA cm−2) by using electricity, wind, solar and thermal energies as power sources and had remarkable long-term stability. In addition, the potential of the OHzS is 1.67 V lower than that of OWS at the j of 10 mA cm−2. The excellent performance of CoFe2O4@NNWs is attributed to the fact that the heterojunction fromed by CoFe2O4 and NNWs effectively regulates the electron density of the sample, thereby improving the kinetics of H* adsorption and the N2H4 dehydrogenation, which can be confirmed by DFT. Second, the continuous electron transport channel provided by NNWs improves the electrical conductivity of the sample. In addition, the 2D CoFe2O4 nanosheets grown on NNWs not only expose more catalytic active sites, but also provide a fast channel for the diffusion of the electrolyte.

PdNPs/NiNWs as a welding tool for the synthesis of polyfluorene derivatives by Suzuki polycondensation under microwave radiation

Conjugated polymers are promising tools to differentiate various types of semiconducting single-walled carbon nanotubes (s-SWCNTs). However, their synthesis is challenging. Insufficient control over molecular weights, and unpredictive/unrepeatable batches hinder possible applications and scale-up. Furthermore, commercial homogeneous catalysts often require inert conditions and are almost impossible to recycle. To overcome these problems, we present a nanocatalyst consisting of magnetic nickel nanowires decorated with highly active palladium nanoparticles. A two-step wet chemical reduction protocol with the assistance of sonochemistry was employed to obtain a heterogeneous catalyst capable of conducting step-growth Suzuki polycondensation of a fluorene-based monomer. Additionally, we enhanced the performance of our catalytic system via controlled microwave irradiation, which significantly shortened the reaction time from 3 d to only 1 h. We studied the influence of the main process parameters on the yield and polymer chain length to gain insight into phenomena occurring in the presence of metallic species under microwave irradiation. Finally, the produced polymers were used to extract specific s-SWCNTs by conjugated polymer extraction to validate their utility.

Free-standing films of nickel nanowires anchored with Ni3S2 nanosheets for stable Li anodes

A free-standing 3D scaffold of nickel nanowires decorated with lithiophilic Ni3S2 nanosheets was successfully constructed for stable Li anodes.

Optical analysis of aligned Ni nanowire arrays with different degree of oxidation for terahertz polarizer application

The optical properties of aligned nickel nanowire arrays (NiNWAs) with different degrees of oxidation for terahertz (THz) polarizer applications have been investigated by using THz time-domain spectroscopy. In frequency-domain spectra, the full width at half maxima of transmitted peaks was broadened and the peak positions have a blue shift with increasing oxidation levels, besides the enhancement in peak intensity. It is indicated that the oxidation of Ni nanowires (NWs) has a significant influence on the interaction between Ni NWs and THz wave. The transmittance of the aligned NiNWAs increases with annealing temperature increasing. Conversely, the degree of polarization and extinction ratio (ER) decreases. A corresponding relationship between the change of ER and degree of oxidation is summarized by means of thermogravimetric analysis. The change of ER for the annealing sample with the degree of oxidation of 0.507% is 27.32%, which induced the polarization properties of aligned NiNWAs to be sensitive to the oxidation of Ni NWs. These findings can provide new positive features in the development of future polarization-based device applications for THz electronics and photonics.

Novel use for metal nanowires – synthesis, characterization and application of nickel and silver nanowires in the process of ethanol dehydration via pervaporation

In order to improve the separation properties of water/ethanol mixture, silver (Ag-NWs) and nickel nanowires (Ni-NWs) were used as a filler for alginate membranes. An effective separation of water from ethanol molecules was demonstrated using the unusual shape, size, quantity and properties of the nanowires. The synthesized nanowires were obtained by the polyol process (silver) and the reduction with hydrazine in an alkaline environment intensified by the action of an external magnetic field (nickel). To characterize the obtained nanowires and membranes, SEM, TEM, SQUID magnetometer and EDS measurements were performed. Moreover, the hydrophilicity of investigated membranes was measured using contact angle and degree of swelling. The explanation of the phenomena occurring during the permeation of water and ethanol molecules through the investigated membranes was performed according to the random walks simulation. The study shows that the efficiency of the process is related to the structure and hydrophilicity of the membranes, the formation of networks that facilitate the transport in the membrane and magnetic properties of the nickel nanowires. The highest value of the separation coefficient was obtained for the membrane filled with 50 mg (5 ml) of nanowires. In this case, flux and separation coefficient ​​were equal to 1.1 kg·m−2·h−1 and 878 for membranes with silver and 1.6 kg·m−2·h−1 and 1415 for nickel nanowires, respectively.

Structural control of nickel nanowire arrays for use as non‐enzymatic glucose sensors

AbstractA series of non‐enzymatic electrochemical glucose sensors were prepared by template‐assisted electrodeposition of nickel to produce nickel nanowire arrays (NiNWAs) of varying lengths. These electrodes were analyzed for their performance as non‐enzymatic glucose sensors, in order to explore the relationship between nanowire structure and electrochemical sensor performance. All of the NiNWAs, regardless of length, had linear responses to glucose in the 0.05–10 mM range. However, an inverse relationship between wire length and sensitivity was observed: the shortest of the NiNWAs had a sensitivity of 160 μA mM−1 cm−2, while the longest NiNWA had a sensitivity of only 100 μA mM−1 cm−2. This indicates that, with no other change to material parameters, choosing an optimum length of nanowire provides significant improvement in performance. No change in electrochemical mechanism was observed by cyclic voltammetry, and no significant loss of selectivity was observed with varying nanowire length. This study demonstrates that the structural optimization of an electrode can provide significant performance enhancement for nickel‐based electrochemical sensors.

Ni nanowires decorated with Pd nanoparticles as an efficient nanocatalytic system for Suzuki coupling of anisole derivatives

Suzuki-Miyaura reaction enables the formation of biaryl compounds containing diverse functional groups. This work reports the development of a nanocatalytic system, which enhances the coupling of anisole derivatives using this reaction framework. Composite nanocatalysts were prepared by decorating nickel nanowires (Ni NWs) made in-house with spherical palladium nanoparticles (Pd NPs). Sonochemical deposition of noble catalytic centers on metallic nanowires proved to be fast and effective under mild conditions. Precise control of the concentration of Pd NPs on the nanowire surface enabled studying the impact of the content of noble metal on the reaction course. The lowest evaluated load of Pd (0.34 %) exhibited the best catalytic performance. Moreover, it was noted that the application of microwaves considerably increased the catalytic activity of the system due to the formation of hot spots on Pd NPs. As a result, the reaction times were shortened substantially without negatively influencing the yields of the transformations. The proposed novel approach for nanocatalyst design should inspire further studies in modern organic chemistry, especially since the proposed catalytic system is highly efficient and entirely reusable.

(Invited) Non-Enzymatic Glucose Sensor Fabricated By Ni-Nanowires Decorated Graphene Gated FETs

In this study, an innovative non-invasive glucose sensor made of nickel nanowire-decorated graphene-gated field-effect transistors is demonstrated. Due to the redox reaction between nickel nanowires and glucose molecules in weakly alkaline solution, electron exchange occurs when Ni(III) reacts with glucose to form Ni(II) and gluconolactone. In order to improve the sensitivity of the glucose sensor and reduce the detection limit, we compared the characteristics of the glucose sensor fabricated by nickel nanowires on gold surface and graphene/gold surface, respectively. Since the CVD-grown graphene film has excellent electrical conductivity and no defects, the electrons generated by the redox reaction can be quickly and evenly dispersed and are not easily neutralized, resulting in a change on the gate potential, thereby affecting the current between the source and the drain metal, and then the glucose concentration in the solution can be deduced. It can be seen from the experiments that the glucose sensor with graphene film has better current stability, lower detection limit and better linear relationship between current and concentration. The demonstrated nickel wire-decorated graphene-gated FET biosensor can be used for the quantification of glucose with a linear range of 10-50 mM and a detection limit of 51nM. Figure 1

(Invited) An Overview of Electrochemistry Application to Additive Manufacturing

Additive manufacturing (AM) is the process of creating three-dimensional (3D) objects from digital models through the sequential deposition of material in layers. This talk will highlight how researchers have used electrochemical research in additive manufacturing and will provide insights into how technology can be exploited to formulate novel microstructures and optimize the manufacturing process. Electrochemical 3D printing is a relatively new form of AM that creates metallic structures through the electrochemical reduction of metal ions from solutions onto conductive substrates. It involves localized electrochemical deposition of metals combined with additive manufacturing principles to achieve Electrochemical Additive Manufacturing (ECAM). The talk will also focus on the formulation of metal precursor inks to produce novel metallic microstructures and nanoalloys containing multiple metals. These inks are used with AM techniques to fabricate 2D and 3D printed conductive structures directly onto a substrate. Examples include aligned nickel nanowires over large areas, which provide opportunities to produce structures with enhanced anisotropic electrical and magnetic properties. Nanoalloy films printed using metal precursor inks have a variety of important applications involving local control of alloy composition in AM part. Examples include the facile formation of layered nanostructures and electrical conductivity with oxidative stability. The talk will conclude with current research on electropolishing of AM parts. AM while capable of producing complex-shaped metal parts with intricate internal geometries and lattice structures struggles to make parts with the smooth surface finish required for many applications. Polishing interior surfaces inaccessible to traditional surface polishing methods is a challenge. Electropolishing is increasingly being used as a post-treatment option for metal AM parts due to its non-contact nature and ability to finish complex internal features.

Size and kink effects on thermal conductivity in nickel nanowires

The potential applications of nanowires in thermal management and thermoelectric energy conversion have sparked extensive research on thermal transport in various nanowires. Nickel nanowires, with their unique properties and promising applications, have been extensively studied. However, the influence of size, particularly the impact of kink structures, on the thermal transport behavior in nickel nanowires remains unclear. In this paper, we employed electron-beam lithography and liftoff techniques to fabricate suspended nickel nanowires with varying sizes and kinks to experimentally investigate the size and kink effect on the thermal conductivity. The experimental results revealed that the thermal transport behavior of nickel nanowires is significantly influenced by both size and kink effects. Notably, as the nanowire size decreases, the thermal conductivity also decreases. Furthermore, we discovered that the thermal conductivity can be adjusted by altering the number and angle of kinks. Increasing the number of kinks from 18 to 36 resulted in a significant decrease in thermal conductivity. In contrast, as the kink angle decreased from 157° to 90°, the thermal conductivity also decreased. However, intriguingly, when the kink angle was further decreased from 90° to 43°, the thermal conductivity increases. This non-monotonic change in thermal conductivity with the kink angle provides an interesting insight into the intricate behavior of heat carriers in kinked nickel nanowires. Additionally, we found that varying the alloy elements can profoundly alter the thermal conductivity of nanowires with kinks. These results offer valuable insights into the behaviors of heat carriers, including electrons and phonons, during heat transfer in nickel nanowires.

Study on Pickering emulsions co-stabilized by multiple particles for building MXene-based multifunctional composite foam

Pickering emulsion, an emulsion prepared by replacing conventional surfactants with solid particles, has been extensively used to construct a variety of functional materials especially 3D porous foams or aerogels. Ti3C2Tx MXene have recently garnered tremendous attention and considered as a promising candidate for the construction of functional nanomaterials due to their fascinating properties. However, it remains a challenge to construct MXene-based composite porous materials. Herein, the Pickering emulsion co-stabilized by multiple kinds of particles and the subsequent MXene-based multifunctional composite foam were studied. The formation mechanism of Pickering emulsions stabilized by cellulose nanofibrils (CNF), nickel nanowires (Ni NW), and Ti3C2Tx MXene was investigated along with their stabilization mechanism in a complex water-oil environment. The final Pickering emulsions exhibited excellent stability over a wide pH range (5−11) and ionic strength (0–400 mM). Further, the CNF/MXene/Ni (CMN) composite foam was prepared by freeze-drying the emulsion gel. The as-prepared foam exhibited a minimum reflection loss of −30.2 dB at 2.8 GHz frequency. Moreover, the foam also exhibited promising photothermal conversion behavior, maintaining a temperature of up to approximately 80.9 °C for 200 s of exposure to 1 Sun. Therefore, this work affords a new and universal method to prepare MXene-based multifunctional porous materials for their potential applications in many areas.

Harmonic oscillations of point soliton (Bloch point) in cylindrical ferromagnetic nanowire

Harmonic oscillations of a point magnetic soliton (Bloch point) located in a domain wall (DW) of a cylindrical ferromagnetic nanowire along the spatial directions of a primitive vortex cell formed by the magnetization vectors at the boundary between the core and the transition zone of the soliton are considered. The possibility of experimental implementation of Bloch point resonant oscillations excited by external alternating magnetic field is shown. In the case of weak attenuation, the maximum values of the resonant frequencies of Bloch points in iron and nickel nanowires are determined, which are 10 and 3 GHz, respectively. These results can be applied in the modern nanotechnologies based on the use of the magnetic properties of ferromagnetic nanowires whose DWs contain Bloch points.

(Invited) Non-Enzymatic Glucose Sensor Fabricated By Ni-Nanowires Decorated Graphene Gated FETs

In this study, an innovative non-invasive glucose sensor made of nickel nanowire-decorated graphene-gated field-effect transistors is demonstrated. Due to the redox reaction between nickel nanowires and glucose molecules, electron exchange occurs when Ni(III) reacts with glucose to form Ni(II) and gluconolactone. Changes in electron concentration are amplified by transistors at the bottom, improving detection sensitivity. In this study, the electrical properties of glucose sensor fabricated from nickel nanowire/graphene/gold surfaces was studied. Since the CVD-grown graphene film has excellent electrical conductivity, the electrons generated by the redox reaction can be quickly and evenly dispersed. The results show that the glucose sensor with graphene film has good current stability, low detection limit and good linear relationship between current and concentration. The demonstrated nickel wire-decorated graphene-gated FET biosensor can be used for the quantification of glucose with a linear range of 10-50 mM and a detection limit of 51nM.

Improving self-supported nanowire arrays using response surface methodology for the synthesis of a H2O2 nanostructured sensor

In this paper, we introduce a data-driven approach for optimizing the design of highly sensitive hydrogen peroxide (H2O2) sensors based on self-supported nickel nanowire (Ni NW) arrays using response surface methodology (RSM). Our goal is to enhance the performance of the sensor by customizing the length of Ni NW while optimizing the working conditions, including the H2O2 concentration and applied potential. Focusing solely on the commercially available porous membranes, we successfully employ RSM to identify the optimal conditions for the sensor: a NW length of 2.64 μm, an optimal concentration of 3.25 mM H2O2, and a detection potential of 0.02 V. We fabricate a sensor with the optimal NW length and validate its performance through comparison to sensors with different NW lengths, such as a planar Ni sensor and a previously investigated nanostructured sensor. Our optimized sensor achieves a 50% reduction in the limit of detection (LOD) and an 18% increase in sensitivity compared with the previously investigated nanostructured sensor. Moreover, the optimized sensor is at least 35 times more sensitive for H2O2 detection than sensors with planar geometries, which are standard in commercial applications. Our results highlight the potential of RSM as a powerful, cost-effective, and theoretically agnostic tool for optimizing nanostructured sensors and accelerating the design-build-test cycle. The optimized H2O2 sensor can be applied in various fields, including the food industry, medical diagnostics, and environmental monitoring. This sensor can significantly enhance glucose detection in non-invasive samples such as tears and saliva when combined with immobilized glucose oxidase enzymes, which is crucial for continuous glucose monitoring in diabetes mellitus patients. The methodology presented in this study allows further extensions to investigate other design variables and sensing materials as well as optimize sensors for detecting different substances, fostering advancements in sensor technologies.

A novel non-enzymatic electrochemical sensor based on NiS/Co3S4@h-Ni NWs core-shell electrode for glucose detection in human serum

To obtain a non-enzymatic electrochemical sensor with good performance such as sensitivity, selectivity, and stability, fine-tuning and rational design of the electrocatalytic material are essential. In this study, a novel catalyst (NiS/Co3S4@h-Ni NWs) with a hierarchical core-shell structure was synthesized in two steps to be used as a non-enzymatic electrode for glucose detection. First, hierarchical nickel nanowires, h-Ni NWs (the core), were prepared by the reduction of Ni2+ ions by hydrazine N2H4, and then the h-Ni NWs are covered with NiS/Co3S4 (the shell) by the hydrothermal method. The resulting NiS/Co3S4@h-Ni NWs showed a core-shell structure with abundant nanotides on the surface and good crystallinity. The prepared sensor exhibited two linearity ranges in the glucose concentration ranges of 0.001–6.57 mM and 6.57–13.32 mM with a sensitivity of 1171.9 μA mM−1 cm−2 and 316.5 μA mM−1.cm−2, respectively, and with a low detection limit of 0.13 μM (S/N = 3) due to its developed core-shell structure that provides excellent conductivity, an efficient mesoporous network, and suitable channels for rapid ion/electron transfer for electrocatalytic activity. In addition, the sensor also showed exceptional selectivity against coexistence interference, good long-term stability, reproducibility, and repeatability. All these excellent results show that the prepared NiS/Co3S4@h-Ni NWs catalyst can be a promising electrode material for glucose detection.