Ni-Co Alloy Research Articles

Evolution of microstructure and properties of nanocrystalline NiCo alloy under high-energy laser shock

In this study, nanocrystalline NiCo alloy was prepared through electrodeposition and subjected to high-energy laser shock (HELS) treatment to investigate the influence of laser shock on the microstructures and properties. An analysis of phase composition, microstructural evolution, texture evolution, and hardness was conducted. The results indicated that under HELS, there was no change in phase composition, while there was a slight reduction in grain size, as well as in the quantities of Low-angle grain boundaries (LAGBs) and twin boundaries (TBs). The texture evolution revealed that HELS led to a more uniform overall texture due to grain boundary (GB) mediate deformation mechanisms, along with the generation of a significant amount of 9R phases, causing a shift in texture orientation from (110) to (100). The internal structure of nanocrystalline NiCo showed an accumulation of numerous dislocations post-laser shock, with randomly oriented dislocations interacting to form Lomer-Cottrell Locks (L-C Locks) and 9R phases. Additionally, interactions with large stacking faults (SFs) also resulted in their dissociation into multiple 9R phases. The hardness enhancement was mainly attributed to the accumulation of dislocations within the grain and the generation of a significant quantity of 9R phases.

Enhanced Methanol Electrooxidation and Supercapacitive Performance via Compositional Engineering of Colloidal Ni-Co Alloying Nanoparticles.

Among renewable energy technologies, particular attention is paid to electrochemically transforming methanol into valuable formate and storing energy into supercapacitors. In this study, we detailed a simple colloidal-based protocol for synthesizing a series of alloy nanoparticles with tuned Ni/Co atomic ratios, thereby optimizing their electrochemical performance. With the addition of 1 M methanol in 1 M KOH, the optimized composition was able to electrochemically produce formate at 0.149 mmol cm-2 h-1 with a Faradaic efficiency up to 95.1% at 0.6 V versus Hg/HgO within a 22-hour testing period. In 1 M KOH solution without methanol, the supercapacitive performance was achieved at a specific capacitance of over 1500 F g-1, and outstanding cycling stability with only approximately 20% decay after continuous 10000 charging-discharging cycles. These results underscore that the prepared Ni-Co alloy nanoparticles serve as multi-functional electrodes for electrochemical energy conversion and storage, particularly in the MOR and supercapacitors applications.

Formate and CO* Radicals Intermediated Atmospheric CO2 Conversion over Co-Ni Bimetallic Catalysts Assembled on Diatomite.

There exists an imperative exigency to ascertain catalysts of cost-effectiveness and energy efficiency for the facilitation of industrial CO2 methanation. In this area, the dual metal synergistic enhancement of the metal-support interaction emerges as a highly promising strategy. Here, Diatomite (Dt) was used as the support, and a series of CoyNi/Dt (Co as the first component and Ni as the second component) composite catalysts were constructed using an ultrasound-assisted coimpregnation method. Different Co/Ni molar ratios had a significant impact on the phase structure, chemical properties, morphological characteristics, and NiCo crystal structure of the xCoyNi/Dt materials. When the Co/Ni molar ratio was set to 2.0, a Ni-Co alloy was obtained, which is the key to improve the catalytic activity. Compared to the other xCoyNi/Dt catalysts, the bimetallic catalyst 2Co1Ni/Dt exhibited superior CO2 catalytic performance and stability, achieving a 76% CO2 conversion and 98% CH4 selectivity at 425 °C. The in situ DRIFTS results indicated that CO2 methanation over the 2Co1Ni/Dt catalyst followed the reaction pathway with formate and CO* radicals as the intermediates.

Layered double hydroxides-derived CoNi alloy nanoparticles encapsulated by porous N-doped carbon nanofibers as efficient methanol electrocatalysts for alkaline direct methanol fuel cells

The exploration of inexpensive electrocatalysts possessing high activity and increased stability to replace precious metal catalysts in the methanol oxidation reaction (MOR) is highly desirable for alkaline direct methanol fuel cells (ADMFCs). This study presents a novel approach to synthesize layered double hydroxides (LDHs)-derived CoNi alloy nanoparticles confined within porous N-doped carbon nanofibers (CoNi@NCNFs) via facile electrospinning and pyrolysis for methanol electrooxidation. The one-dimensional N-doped carbon nanofibers could effectively prevent nanoparticle agglomeration during the pyrolysis of LDH precursors. The optimized CoNi@NCNF3–900 composite exhibits exceptional catalytic activity (80.3 mA cm−2) for MOR in alkaline solution, attributed to its hierarchical porous structure, high surface area, and abundant accessible active sites. Furthermore, the catalyst demonstrates competitive electrocatalytic stability, retaining over 90 % of its initial current density after 1000 consecutive cyclic voltammetry (CV) cycles. Notably, a single-cell ADMFC assembled with CoNi@NCNF3–900 as the anode catalyst achieves a promising maximum power density of 29.5 mW cm−2, highlighting the potential of CoNi@NCNF3–900 for application in DMFC technology and clean energy sources.

Co–doped nitrogenated carbon nanotubes encapsulating CoNi alloys as bifunctional catalysts for urea-assisted rechargeable Zn-air battery

Co–doped nitrogenated carbon nanotubes encapsulating CoNi alloys as bifunctional catalysts for urea-assisted rechargeable Zn-air battery

NiCo alloy-decorated nitrogen-doped carbon double-shelled hollow polyhedrons with abundant catalytic active sites to accelerate lithium polysulfides conversion

Lithium-sulfur (Li-S) batteries have received significant attention due to their high theoretical energy density. However, the inherent poor conductivity of S and lithium sulfide (Li2S), coupled with the detrimental shuttle effect induced by lithium polysulfides (LiPSs), impedes their commercialization. In this study, we develop NiCo alloy-decorated nitrogen-doped carbon double-shelled hollow polyhedrons (NC/NiCo DSHPs) as highly efficient catalysts for Li-S batteries. The distribution of NiCo alloy on both the inner and outer shells provides abundant catalytic active sites, effectively adsorbing LiPSs, mitigating the shuttle effect, and promoting the conversion between LiPSs and Li2S, even at high sulfur loadings. This results in enhanced redox kinetics within the Li-S system. Moreover, the highly conductive carbon material framework, enriched with carbon nanotubes and graphitic carbon layers, can greatly promote the efficient electron transportation. Additionally, the improved ion diffusion rates benefiting from the hollow structure can also be realized. By harnessing these synergistic effects, Li-S batteries incorporating the double-shelled NC/NiCo DSHP catalysts achieved a high specific capacity of 1310 mAh/g at 0.2C and a superior rate performance of 621 mAh/g at 4C. Furthermore, excellent cycling performance with ultralow capacity fading rate of only 0.045 % per cycle after 800 cycles at 1C was achieved. When sulfur loading reaches 6 mg cm−2, a high capacity of 4.6 mAh cm−2 at 0.1C after 100 cycles further validates the practical potential of this design. This study presents an innovative approach to alloy catalyst design, offering valuable insights for future research of Li-S batteries.

Machine learning prediction of microhardness and corrosion current density of Ni-Co alloys produced by scanning jet electrodeposition

ABSTRACT Scanning jet electrodeposition (SJE) is a promising method for electrodeposition. Integrated with automation and machine learning, intelligent electrodeposition can be achieved. In this study, a machine learning method was used to develop the relationship between the process parameters and properties of Ni-Co alloys produced by SJE. To evaluate the various models, the coefficient of determination (R 2), mean absolute percentage error (MAPE), and root mean square error (RMSE) were calculated as performance metrics. The multivariate nonlinear regression (MNR) model shows a higher R 2, lower MAPE and RMSE values, and better performance in both the training and testing sets, indicating superior approximation and prediction accuracies for microhardness. A back-propagation artificial neural network (BP-ANN) shows stable R 2 value of closest to 1, and the lowest MAPE and RMSE for corrosion current density and presents an exceptional generalisation ability. Finally, under the present experimental conditions, the highest microhardness and corresponding process parameters were determined using the MNR model, and the lowest corrosion current density was optimised using the BP-ANN model.

Highly efficient selective hydrogenation of furfural to tetrahydrofurfuryl alcohol over MOF-derived Co-Ni bimetallic catalysts: The effects of Co-Ni alloy and adsorption configuration

The targeted conversion of furfural (FA) over inexpensive catalyst is a critical and challenging project. Herein, CoNi alloy catalysts (xCoyNi/C) were prepared through one-step pyrolysis of metal–organic frameworks and used in furfural (FA) hydrogenation to tetrahydrofurfuryl alcohol (TFOL). The formation of CoNi alloy leads to a reconfiguration of the electronic structure on the metal surface, which affects the adsorption of functional groups on FA and furfuryl alcohol (FOL). In situ FT-IR analysis and DFT calculations verify that bimetallic CoNi alloy catalyst exhibits more suitable reactants adsorption and hydrogenation rate in comparison with the monometallic Co and monometallic Ni catalysts. Meanwhile, CoNi alloy significantly reduces the activation barrier from FOL to TFOL. Hence, the 1Co1Ni/C catalyst gives the highest TFOL yield of > 99 %. This study provides a simple strategy for the preparation of alloy catalysts for tuning product selectivity and presents practical potential for upgrading biomass-derived platform molecules.

Boosting Dry Reforming of Methane Over NiCo/CeO2 Catalysts Treated by Hydrogen Plasma

ABSTRACTNickel (Ni)‐based catalysts are prospective materials for dry reforming of methane (DRM) reaction, but suffer from coke formation and limited activity for CO2 conversion. To improve the reactivity of Ni‐based catalysts, a promising strategy is introducing cobalt (Co) metal. Here, we construct highly efficient NiCo sites on CeO2 support by H2 plasma, which enables the catalyst to obtain a remarkable increase in DRM reaction than the samples treated by conventional H2 reduction. H2 plasma treatment results in the formation of highly dispersed NiCo alloy nanoparticles and high‐concentration oxygen vacancy. These features create large numbers of highly active sites to boost the activation of CH4 and especially CO2 and their catalytic reactions, resulting in strong coke resistance in the DRM reaction.

Innovative strategy for corrosion protection and drag reduction in coiled tubing: Design, fabrication, and performance evaluation

To improve the anti-corrosive and drag-reducing properties of 70 carbon steel coiled tubing and extend its service life, we presented an innovative approach involving composite electroplating. This method allows for the deposition of high-performance, anti-corrosive, and drag-reducing coatings on the inner walls of coiled tubing. And a continuous, uniform, and dense Ni-Co-Al2O3 coating was successfully prepared on the inner wall of coiled tubing. This economically viable technique was systematically applicable in industrial settings for enhancing drag reduction and corrosion resistance in continuous petroleum pipelines, offering a practical solution for manufacturing functional coatings with desirable properties. Furthermore, considering the inhibitory effect of Co(OH)2 on Ni deposition, we developed a novel anomalous co-deposition model for Ni-Co binary alloys. The simulation results using the COMSOL® demonstrated a high correlation with the experimental data, underscoring the model as effective for controlling and predicting the composition and structure of Ni-Co coatings.

Enhancing the electromagnetic shielding and mechanical properties of CF/PEEK composites via low-concentration fluff and Ni-Co alloy plating

Carbon Fiber Reinforced Composites (CFRC) are increasingly used in aircraft to minimize weight and maximize structural designability. However, CFRCs have limitations in electrical conductivity and Electromagnetic Interference (EMI) resistance. This study introduces a process to overcome these drawbacks by chemically plating Carbon Fiber (CF) fabrics with a thin layer of Nickel-Cobalt (Ni-Co) alloy, thereby improving electrical conductivity. Subsequently, Sulfonated Polyether Ether Ketone (SPEEK) was applied to the Nickel-Cobalt coated Carbon Fibers (NiCo@CF). The resulting fuzzy surface effectively enhanced the interfacial interactions within the PEEK matrix. The results showed that the tensile strength, tensile modulus, flexural strength, and flexural modulus of the composite panels treated with 0.1 wt.% SPEEK sizing significantly increased by 32.3 %, 26.0 %, 167.9 %, and 20.7 %, respectively, compared to NiCO@CF/PEEK composite panels treated with no SPEEK sizing agent. Additionally, the introduction of SPEEK fostered a shift in the primary fracture mechanism from fiber pull-out or debonding to fiber fracture. Remarkably, compared to CF/PEEK composites, the electromagnetic shielding efficiency of NiCo@CF/PEEK was increased by 88.98 %, reaching 46.15 dB. Long-term testing of the S-NiCO@CF/PEEK composites in a humid and hot environment confirmed consistent electromagnetic and mechanical properties, alongside good fatigue and aging resistance. These advances make the S-NiCO@CF/PEEK composites promising for broader applications in the aircraft and aerospace fields.

Smart utilization of bimetallic NiCo alloy supported carbon dots and sulfur quantum dots derived 3D nanocomposite for oxygen evolution reaction

The increasing demand for highly active and stable electrocatalysts for the oxygen evolution reaction (OER) in future energy-conversion systems has driven researchers to explore novel alternatives to Pt-based catalysts. Among these alternatives, zero-dimensional quantum dots have emerged as promising candidates due to their high surface area and intrinsic electrocatalytic activity, which lead to significant breakthroughs in electrocatalytic performance. Herein, we conducted a preliminary investigation into the application of bimetallic NiCo alloy deposited on metal-free quantum dots (carbon dots and sulfur quantum dots) derived nano sponge for the oxygen evolution reaction. The synthesized NiCo-CDs-800 exhibited remarkable electrocatalytic OER activity, achieving a current density of 10 mA cm−2 with only 221 mV overpotential, far surpassing commercial RuO2 electrocatalysts. The excellent electrocatalytic activity can be attributed primarily to high electrochemically active area (168.97 mF cm−2), the presence of large proportion of oxygen vacancies (68.61 %), rich pyridinic nitrogen structure (29.30 %) with strong water adsorption, and synergistic effect of bimetals as supported by density functional theory calculations. Meanwhile, the newly prepared NiCo-SQDs-700 under the similar procedure demonstrate a satisfied OER performance and competing stability when compared to NiCo-CDs. These findings open a new avenue for the application of metal free CDs and SQDs to the growing family of metal@QDs.

Efficient Electrocatalytic Oxidation of Glycerol to Formate Coupled with Nitrate Reduction over Cu-Doped NiCo Alloy Supported on Nickel Foam.

Electrooxidation of biomass-derived glycerol which is regarded as a main byproduct of industrial biodiesel production, is an innovative strategy to produce value-added chemicals, but currently showcases slow kinetics, limited Faraday efficiency, and unclear catalytic mechanism. Herein, we report high-efficiency electrooxidation of glycerol into formate via a Cu doped NiCo alloy catalyst supported on nickel foam (Cu-NiCo/NF) in a coupled system paired with nitrate reduction. The designed Cu-NiCo/NF delivers only 1.23 V vs. RHE at 10 mA cm-2, and a record Faraday efficiency of formate of 93.8 %. The superior performance is ascribed to the rapid generation of NiIII-OOH and CoIII-OOH species and favorable coupling of surface *O with reactive intermediates. Using Cu-NiCo/NF as a bifunctional catalyst, the coupled system synchronously produces NH3 and formate, showing 290 mV lower than the coupling of hydrogen evolution reaction, together with excellent long-term stability for up to 144 h. This work lays out new guidelines and reliable strategies from catalyst design to system coupling for biomass-derived electrochemical refinery.

Efficient Electrocatalytic Oxidation of Glycerol to Formate Coupled with Nitrate Reduction over Cu‐Doped NiCo Alloy Supported on Nickel Foam

AbstractElectrooxidation of biomass‐derived glycerol which is regarded as a main byproduct of industrial biodiesel production, is an innovative strategy to produce value‐added chemicals, but currently showcases slow kinetics, limited Faraday efficiency, and unclear catalytic mechanism. Herein, we report high‐efficiency electrooxidation of glycerol into formate via a Cu doped NiCo alloy catalyst supported on nickel foam (Cu−NiCo/NF) in a coupled system paired with nitrate reduction. The designed Cu−NiCo/NF delivers only 1.23 V vs. RHE at 10 mA cm−2, and a record Faraday efficiency of formate of 93.8 %. The superior performance is ascribed to the rapid generation of NiIII−OOH and CoIII−OOH species and favorable coupling of surface *O with reactive intermediates. Using Cu−NiCo/NF as a bifunctional catalyst, the coupled system synchronously produces NH3 and formate, showing 290 mV lower than the coupling of hydrogen evolution reaction, together with excellent long‐term stability for up to 144 h. This work lays out new guidelines and reliable strategies from catalyst design to system coupling for biomass‐derived electrochemical refinery.

Exploring stacking fault energy with the axial Ising model: A renewed approach

In this work we revisit the axial Ising model for computing intrinsic stacking fault energies (γISF), which are important in alloy design. We find that the supercell approach, which directly compares the energies of fcc stacking with and without a fault, is a specific solution of the Ising model and is the most elegant and efficient among the solutions of the same order of accuracy. Contrary to the traditional belief that only the supercell approach can capture the effect of local chemistry, we demonstrate that local chemistry also influences γISF in the axial Ising model. We also propose a new formula γISF=5EABABC−5EABC, which is similarly efficient, simpler, and more accurate compared to the widely used γISF=EAB+2EABAC−3EABC. We tested the new formula on pure Ni, Ni-Co alloys, and Cr-Mn-Fe-Co-Ni high entropy alloys and found satisfactory results.

Gelation-pyrolysis strategy for fabrication of advanced carbon/sulfur cathodes for lithium-sulfur batteries

The development of high-performance carbon-based composite hosts play decisive roles in the electrochemistry of lithium sulfur batteries. Herein, a novel metal-ion induced gelation self-assembly technology is reported to construct sodium alginate carbon (SAC) based polar hierarchical carbon composites with cross-linked network architecture and in-situ co-grown cross-linked polar nanoparticles. Interestingly, it shows high versatility to an extensive array of materials including metals, alloys, and metallic oxides. As a representative, NiCo alloy nanoparticles are chosen to obtain the SAC/NiCo composite host for sulfur in LSBs, which possess superior physical/chemical adsorption capabilities and catalytic conversion kinetics to polysulfide in virtue of synergistic interaction between the hierarchical pore structures and NiCo catalyst. The designed SAC/NiCo-S cathode shows superior electrochemical performance with excellent rate capacity (2 C: 693.5 mAh/g) and enhanced cycling stability (764.3 mAh/g at 0.1 C after 240 cycles). This work provides a straightforward approach for fabricating multifunctional carbon composites with adjustable component for advanced energy storage system.

CoNi Alloy Modified Separators for High-Capacity and Long Cycle Lithium–Sulfur Batteries

CoNi Alloy Modified Separators for High-Capacity and Long Cycle Lithium–Sulfur Batteries

Comparison between the structural characteristics and process activity of bulk and mesoporous Ni-Co-Ce/Al2O3 catalysts in the dry reforming of methane

Dry reforming of methane (DRM) is a potential way to exploit greenhouse gases and generate hydrogen. Catalyst deactivation is the biggest DRM commercialization obstacle. Lately, Ni-Co bimetallic catalysts have demonstrated improved carbon resistance over Ni-based catalysts. The aim of this research is not just to investigate the impact of Ni-Co catalysts on the DRM activity, but also to evaluate the Ni-Co alloy creation effect on the catalyst characteristics and activity. Mesoporous alumina (MA) was used as a catalyst support for Ni-Co particles in this process and its structure and activity were compared to those of bulk alumina (BA) supported catalysts. In addition, cerium was included into all of the catalysts developed as a suitable promoter for reducing the amount of deposited coke. The results obtained from the XRD and nitrogen adsorption/desorption analysis indicated the formation of a mesoporous structure and nanocrystalline morphology in the Ni-Co/MA samples, as compared to the Ni-Co/BA ones. The results showed that the bimetallic 2Ni-1Co-1Ce/MA sample had the best catalytic activity, with a CH4 conversion of 98.30 %, CO2 conversion of 96.35 %, and H2 yield of 96.30 % at 700 °C.

Hydrogen evolution coupled with microplastic upcycling in seawater via solvent-free plasma F-functionalized CoNi alloy catalysts

The deleterious impacts of marine polyethylene terephthalate (PET) microplastic pollution on aquatic organisms have garnered global concern. Crafting a more cost-effective method to derive high value-added products from these microplastics is a pivotal challenge in marine resource reuse. This study introduces a strategy for electrooxidation of PET microplastics coupled with seawater electrolysis for green hydrogen production, resulting in value-added chemical formic acid at the anode and hydrogen gas at the cathode. Specifically, a catalyst composed of carbon nanotube-interconnected CoNi alloy-loaded carbon nanocages was fabricated, and F were doped onto the catalyst surface via solvent-free CF4 plasma treatment. Owing to its unique hollow 1D/3D interconnected structure, the synergistic effect of the CoNi alloy, and the ease of reconstruction of metal-F bonds in an alkaline environment, the prepared electrocatalyst exhibited excellent performance in the hydrogen evolution reaction and oxygen evolution reaction, the current density of 10 mA cm−2 was obtained at the overpotential of 187 mV and 315 mV, respectively. Furthermore, the proposed coupling strategy achieved a potential saving of 165 mV at a current density of 10 mA cm−2. This research offers promising prospects for the development of “marine hydrogen mining” and the management of ocean microplastics.

Understanding the Self‐Reconfiguration Properties of a Novel Spinel‐Type High‐Entropy Catalyst

AbstractHigh‐entropy oxides (HEOs), known for their excellent thermodynamic stability due to their high‐entropy effect. In this study, high‐entropy (NixAlCoCrMn)3O4 oxides of spinel structure were synthesized by sol‐gel method. This HEO has a self‐reconfiguration properties in the reaction, and its internal Ni and Co ions exsolve to form a uniformly dispersed NiCo alloy on the surface. The increase of Ni content promotes the exsolution of Ni and Co ions from the interior of the spinel. The high‐entropy with a large number of oxygen vacancies not only possesses a stable structure to limit the migration of NiCo alloys, but also enhances the hydrogen overflow. In the CO methanation reaction, it has 99 % CO conversion with 87 % methane selectivity within 400 °C, and it is stable in the long‐term test. This work provides a new idea for exploring the use of high‐entropy materials to improve thermal catalytic activity and stability.