Pd-Ni Alloys Research Articles

Design of Heusler Precipitation Strengthened NiTi- and PdTi-Base SMAs for Cyclic Performance

For a wide range of actuation applications, the performance of NiTi-based shape memory alloys is limited by cyclic instability associated with accommodation slip. For medical applications, low-Ni compositions are also desirable. Increasing yield strength via precipitation of a coherent nanoscale Ni2TiAl-type Heusler phase from a supersaturated B2 matrix is an effective approach for eliminating slip in order to improve the stability of the functional response and increase the structural fatigue life. Quaternary additions that partition into the L21 Heusler phase, such as Zr or Pd, are favorable for reducing interphase misfit and maintaining coherency during aging. Phase relations and precipitation kinetics in quaternary Ni(TiZrAl), low-Ni (PdNi)(TiAl), and Ni-free (PdFe)(TiAl) systems are summarized from TEM and atom probe tomography data in the literature. Strengthening behavior during isothermal aging is compared in the NiTiZrAl and PdNiTiAl systems, and recent work characterizing a high-strength, low-Ni “Hybrid” (PdNi)(TiZrAl) alloy is presented. A systems design approach is taken in which an optimal microstructure for peak strengthening is identified while other property objectives such as transformation temperature, misfit, radiopacity, and biocompatibility are satisfied.

Highly Active Bimetallic Nickel–Palladium Alloy Nanoparticle Catalyzed Suzuki–Miyaura Reactions

AbstractA bimetallic Ni–Pd alloy nanoparticle catalyst with a low palladium content (Ni0.90Pd0.10 nanocatalyst) was prepared and its catalytic performance in Suzuki–Miyaura reactions was evaluated along with that of other Ni–Pd nanocatalysts (with varying Ni/Pd molar ratios in the range of ≈0.25–0.75) and the corresponding monometallic, Ni and Pd, analogues. Notably, the bimetallic Ni0.90Pd0.10 alloy nanocatalyst performed exceptionally well for the synthesis of biaryls by employing a wide range of substituted aryl halides and arylboronic acids having electron‐donating and electron‐withdrawing groups, and they exhibited high recyclability in water/ethanol solution at moderate reaction temperatures. Catalyst poisoning tests and leaching experiments inferred the heterogeneous nature of the Ni0.90Pd0.10 nanocatalysts. The significant synergistic interactions between Ni and Pd account for the observed high catalytic efficacy of the Ni0.90Pd0.10 nanocatalyst.

Catalytic performance of Pd–Ni bimetallic catalyst for glycerol hydrogenolysis

Catalytic conversion of glycerol from biodiesel production to value-added chemicals and fuels is actually of great interest for industrial chemical research. Bimetallic catalysts are confirmed superior to monometallic catalysts in terms of catalytic activity and selectivity for glycerol hydrogenolysis. Accordingly, a series of Pd–M (M = Fe, Co, Ni, Cu, Zn) bimetallic catalysts were prepared in this work via coprecipitation to investigate the promoting effect of Pd. The relationship between the catalytic performance and metal-support interaction was also discussed. Through the catalyst screening, Pd–Ni bimetallic catalyst exhibited moderate activity and the highest selectivity towards ethylene glycol. At 493 K and hydrogen pressure of 6.0 MPa, the glycerol conversion and selectivity of ethylene glycol reached 89% and 22% respectively. XRD and TEM patterns showed that the Pd nanoparticles with an average size of ∼4 nm were uniformly dispersed in the supports. H2-TPR revealed that the reduction temperatures of metal oxides were significantly decreased by the introduction of Pd component. XPS curves indicated that unique performance of the Pd–Ni bimetallic catalyst might be attributed to the formation of Pd–Ni alloy. And the required metal-support interaction was assumed responsible for the cleavage of C–C bond and generation of ethylene glycol. In the end, hydrogenolysis reactions for the main products of glycerol conversion were carried out over Pd–Ni catalyst to explore the possible reaction pathways for glycerol hydrogenolysis.

Pd–Ni Alloy Nanoparticles as Effective Catalysts for Miyaura–Heck Coupling Reactions

In this work, Pd–Ni alloy nanoparticles (NPs) were produced by a facile and efficient one-pot synthetic strategy in the presence of oleylamine (OAm) and triphenylphosphine (TPP). Transmission electron microscopy (TEM), energy-dispersive spectrometry (EDS) mapping, inductively coupled plasma atomic emission spectroscopy (ICP-AES), and X-ray diffraction (XRD) were used to investigate the structure of Pd–Ni alloy NPs, which demonstrated that the as-prepared alloy NPs possessed uniform sizes and tunable compositions. Importantly, we found that TPP could affect the morphology of the Pd–Ni alloy. When TPP was absent from the reaction, the morphology of the Pd–Ni alloy was not uniform. In addition, the as-prepared Pd–Ni alloy NPs showed conspicuous composition-dependent catalytic activities for the Miyaura–Heck reaction. In the series of the Pd–Ni alloy NPs, Pd1Ni1 has an excellent effect for the Miyaura–Heck reactions. Furthermore, the Pd–Ni alloy NPs were also effective for different substrates in the Miyaura–...

The stochastic nature of phase transformations in a Pd–Ni alloy after electrolytic hydrogenation

The results of an X-ray diffractometry study of an initially deformed single-phase Pd–25.2 at % Ni alloy sample that were carried out during 460 hours after electrolytic hydrogenation of the sample are presented. Long-term stochastic processes of transformation of the shape of diffraction peaks were found, despite the absence of the hydrogen-rich β-phase in the sample.

A nanoporous palladium-nickel alloy with high sensing performance towards hydrogen peroxide and glucose

The nanoporous (NP) PdNi alloy is easily fabricated by one-step mild dealloying of PdNiAl precursor alloy in NaOH solution. Characterized by the nanoporous network architecture with the ligament size as small as 5nm, NP-PdNi alloy exhibits higher electrocatalytic activity towards the oxidation of H2O2 and glucose compared with NP-Pd and Pd/C catalysts. The electrochemical sensor constructed based on NP-PdNi alloy shows high sensing performance towards H2O2 and glucose with a wide linear range, long-term stability, and fast amperometric response. Moreover, NP-PdNi alloy exhibits high resistance towards Cl− poisoning as well as good anti-interference towards ascorbic acid, urci acid, and dopamine. This work provides a simple and green route to construct highly active and sensitive electrochemical sensor for detecting H2O2 and glucose.

Encapsulation of Mono- or Bimetal Nanoparticles Inside Metal-Organic Frameworks via In situ Incorporation of Metal Precursors.

A facile, in situ metal precursor incorporation strategy is established for good control over the location and composition of metal nanoparticles within metal-organic frameworks (MOFs). This one-step metal precursor incorporation route is successfully applied to the fabrication of ultrafine Pd, Ni, and PdNi alloys to be selectively encapsulated inside the pores of MOFs, achieving superior catalytic activity and stability in the hydrogenation of nitrobenzene.

A strategy for fabricating porous PdNi@Pt core-shell nanostructures and their enhanced activity and durability for the methanol electrooxidation.

Three-dimensionally (3D) porous morphology of nanostructures can effectively improve their electrocatalytic activity and durability for various electrochemical reactions owing to big surface area and interconnected structure. Cyanogel, a jelly-like inorganic polymer, can be used to synthesize various three-dimensionally (3D) porous alloy nanomaterials owing to its double-metal property and particular 3D backbone. Here, 3D porous PdNi@Pt core-shell nanostructures (CSNSs) are facilely synthesized by first preparing the Pd-Ni alloy networks (Pd-Ni ANWs) core via cyanogel-reduction method followed by a galvanic displacement reaction to generate the Pt-rich shell. The as-synthesized PdNi@Pt CSNSs exhibit a much improved catalytic activity and durability for the methanol oxidation reaction (MOR) in the acidic media compared to the commercial used Pt black because of their specific structural characteristics. The facile and mild method described herein is highly attractive for the synthisis of 3D porous core-shell nanostructures.

High-performance PdNi alloy structured in situ on monolithic metal foam for coalbed methane deoxygenation via catalytic combustion.

A monolithic Ni-foam@PdNi(alloy) catalyst is tailored for coalbed methane deoxygenation via galvanically depositing Pd nanoparticles on a Ni-foam surface followed by in situ activation. Experimental and theoretical studies unanimously reveal that the in situ formed PdNi alloy contributes to high activity/selectivity, good stability and oscillation elimination.

Electrochemical Dechlorination of 2-Chlorophenol on Pd/Ti, Ni/Ti and Pd-Ni Alloy/Ti Electrodes

The 2-chlorophenol has been treated by advanced oxidation processes (AOPs) and by electrochemical oxidation, but these methods show several disadvantages, such as: high-energy costs, hazardous substances production and electrode deactivation. To avoid the problems caused by oxidation, electrochemical reduction (dechlorination) was proposed as an alternative and promising method. Pd/Ti, Ni/Ti and Pd-Ni alloy/Ti cathodes were used for electrochemical dechlorination of 2-chlorophenol. The cathodes were prepared by electrodeposition under experimental conditions determined from both a thermodynamic study by using predominance existence and distribution species diagrams and a voltammetric study. The electrodes were characterized by SEM, XRD, and XPS. SEM images showed that Pd-Ni/Ti electrode has a different morphology from that of Pd/Ti and Ni/Ti electrodes and the alloy composition is 45% Pd and 49% Ni mol. XRD analyses showed that Pd-Ni alloy /Ti exhibits a network parameter different from those of Pd/Ti and Ni/Ti electrodes. The XPS proved the formation of Pd-Ni alloy. The efficient dechlorination of 2-chlorophenol to phenol was achieved under electrochemical conditions where proton reduction and atomic hydrogen adsorption took place. The Pd-Ni alloy/Ti electrode had the highest dechlorination efficiency (100% removal) and phenol formation (100% formation) at a potential of −0.40 Vvs Ag/AgCl(s)/KCl(sat).

Catalytic CO2 hydrogenation to formic acid over carbon nanotube-graphene supported PdNi alloy catalysts

Pure formic acid was produced via CO2 hydrogenation over a heterogeneous PdNi alloy catalyst on carbon nanotube-graphene support in water solvent without a base additive.

Hydrogen production by autothermal reforming of methane over NiPd catalysts: Effect of support composition and preparation mode

NiPd/Ce0.5Zr0.5O2/Al2O3 and NiPd/La2O3/Ce0.5Zr0.5O2/Al2O3 catalysts were prepared by incipient wetness co-impregnation method or sequential impregnation method for autothermal reforming of methane (ATR of CH4). The influence of the preparation mode, Ce0.5Zr0.5O2 and La2O3 additives on the physicochemical properties of NiPd supported catalysts and the effect on their activity to produce hydrogen by ATR of CH4 were investigated. Characterization of fresh and spent Ni-based catalysts by X-ray fluorescence spectroscopy, N2 adsorption, X-ray diffraction, H2 temperature-programmed reduction, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were performed. It was demonstrated that support composition determines NiO dispersion as well as reducibility of Ni species through different strength of Ni-support interaction. The preparation method modifies the phase composition and catalyst ability for reduction. The catalyst evolution under reaction conditions was studied. The NiO (∼15 nm) and NiPd alloy (∼18 nm) phases were observed in the spent catalysts. It was found that the Nio/NiO ratio can be regulated by support composition and preparation mode of catalysts. It is demonstrated that studied catalysts provide high methane conversion of 90–100%, CO yield of 55–85% and H2 yield of 55–75% in ATR of CH4 at 750–950 °C. The optimal composition and preparation method of catalyst were selected. The best ATR of CH4 performance is provided by 10 Ni0.5Pd/10Ce0.5Zr0.5O2/Al2O3 catalyst prepared by Pd/Ni sequential impregnation method that can be associated with peculiarity of NiPd particles structure and the optimal ratio between NiO species with different ability for reduction.

에틸렌디아민을 착화제로 사용하는 팔라듐-니켈 합금도금

Powder & Ceramic Materials Division, Korea Institute of Materials Science, 797 Changwon-daero, Changwon, Gyeongnam 642-831, Korea(Received October 20, 2014 ; revised October 27, 2014 ; accepted October 28, 2014)AbstractsElectrodeposition behaviors of Pd-Ni alloys were investigated from the polarization curves in a solutioncontaining ethylenediamine as complexing agent. The microstructure and hardness of electrodeposited Pd-Ni alloys were also characterized. Codeposition of Pd-Ni alloys was successfully performed in the wide currentdensity ranging from 2 to 5000 A·m

Pd and Pd–Ni alloy composite membranes fabricated by electroless plating method on capillary α-Al2O3 substrates

Novel home-made porous capillary α-Al2O3 substrates were used as mechanical supports for the Pd-based composite membranes for hydrogen permeation. The rough surface of the substrates with large open pores were modified by vacuum sol–gel dip-coating followed by high temperature calcination treatment. After the introduction of the electroless plating catalysts of Pd particles on the modified surface by an improved catalyzing process, the defect-free Pd and Pd–Ni alloy thin membranes were deposited by cost-effective and facile electroless plating technique. The Pd composite membranes showed a hydrogen permeance of 2.55 × 10−3 mol/(s m2 Pa0.5) at 500 °C, and 730 for the permselectivity of H2/N2. The Pd–Ni alloy composite membranes showed a hydrogen permeance of 2.74 × 10−3 mol/(s m2 Pa0.5), and 640 for the permselectivity of H2/N2 at the same temperature. The Pd and Pd–Ni membranes showed good long-term permeation stability at 500 °C under hydrogen permeation condition. Moreover, the Pd–Ni alloy composite membrane showed a better hydrogen permeation stability of more than 100 h at 300 °C under hydrogen permeation condition without obvious hydrogen embrittlement occurred.

Monodisperse nickel–palladium alloy nanoparticles supported on reduced graphene oxide as highly efficient catalysts for the hydrolytic dehydrogenation of ammonia borane

Addressed herein is the catalysis of reduced graphene oxide-supported monodisperse NiPd alloy nanoparticles (NPs) (rGO-NiPd) in the hydrolytic dehydrogenation of ammonia borane (AB). This is the first example of the use of NiPd alloy NPs as catalyst in the hydrolytic dehydrogenation of AB. Monodisperse NiPd alloy NPs (3.5 nm) were synthesized by co-reduction of nickel(II) acetate and palladium(II) acetylacetonate in oleylamine (OAm) and borane-tert-butylamine complex (BTB) at 100 °C. The current recipe allowed to control the composition of NiPd alloy NPs and to study the composition-controlled catalysis of rGO-NiPd in the hydrolytic dehydrogenation of AB. Among the all compositions tested, the Ni30Pd70 was the most active one with the turnover frequency of 28.7 min−1. The rGO-Ni30Pd70 were also durable catalysts in the hydrolytic dehydrogenation of AB providing 3650 total turnovers in 35 h and reused at six times without deactivation. The detailed reaction kinetics of hydrolytic dehydrogenation of AB revealed that the reaction proceeds first order with respect to the NiPd concentration and zeroth order with respect to the AB concentration. The apparent activation energy of the catalytic dehydrogenation of AB was also calculated to be Eaapp = 45 ± 2 kJ*mol−1.

Using the developed cross-flow filtration chip for collecting blood plasma under high flow rate condition and applying the immunoglobulin E detection

This paper presents a cross-flow filtration chip for separating blood cells (white blood cells, red blood cells, and platelets) and obtaining blood plasma from human blood. Our strategy is to flow the sample solution in parallel to the membrane, which can generate a parallel shear stress to remove the clogging microparticles on the membrane, so the pure sample solution is obtained in the reservoir. The cross-flow filtration chip includes a cross-flow layer, a Ni-Pd alloy micro-porous membrane, and a reservoir layer. The three layers are packaged in a polymethylmethacrylate (PMMA) frame to create the cross-flow filtration chip. Various dilutions of the blood sample (original, 2 × , 3 × , 5 × , and 10×), pore sizes with different diameters (1 µm, 2 µm, 4 µm, 7 µm, and 10 µm), and different flow rates (1 mL/min, 3 mL/min, 5 mL/min, 7 mL/min, and 10 mL/min) are tested to determine their effects on filtration percentage. The best filtration percentage is 96.2% when the dilution of the blood sample is 10 × , the diameter of pore size of a Ni-Pd alloy micro-porous membrane is 2 µm, and the flow rate is 10 mL/min. Finally, for the clinical tests of the immunoglobulin E (IgE) concentration, the cross-flow filtration chip is used to filter the blood of the allergy patients to obtain the blood plasma. This filtered blood plasma is compared with that obtained using the conventional centrifugation based on the enzyme-linked immunosorbent assay. The results reveal that these two blood separation methods have similar detection trends. The proposed filtration chip has the advantages of low cost, short filtration time, and easy operation and thus can be applied to the separation of microparticles, cells, bacteria, and blood.

Wettability of PdNi(Co)-Cr alloys on Si3N4 ceramic and joining of Si3N4 to Si3N4

Eight kinds of PdNi(Co)-Cr alloys were designed, and their wettability on Si3N4 ceramic was studied with the sessile drop method. Under the vacuum heating condition of 1,523 K/30 min, Pd60-Ni40 alloy showed a contact angle of 28° on Si3N4 ceramic, and the reaction band between it and the Si3N4 consisted of the mixture of (Pd, Ni) solid solution and (Pd, Ni)-silicides. It was found that Cr addition into the Pd-Ni alloys further improved their wettability. Pd60-Co40 alloy gave a contact angle of 134°. When 8 wt.% Cr was added into Pd-Co alloy, its contact angle was remarkably decreased to 44°. The reaction products at the interfaces were examined by SEM equipped with an X-ray energy-dispersive spectrometer, and the corresponding interfacial reaction mechanism was also discussed. The formation of Pd2Si is evident at the interfaces. PdCo(Ni,Si,B)-(20∼25)Cr alloy was designed as a filler metal and was produced into filler foils by a rapidly-solidifying technique, and they were used for the brazing of Si3N4/Si3N4. The Si3N4/Si3N4 joints brazed at 1,523 K for 10 min exhibited an average three-point bend strength of 107.7 MPa at room temperature.

Pd-Ni alloy nanoparticle doped mesoporous SiO₂ film: the sacrificial role of Ni to resist Pd-oxidation in the C-C coupling reaction.

A Pd-Ni alloy nanoparticle (NP) doped mesoporous SiO2 film was synthesized using a one pot inorganic-organic sol-gel process in the presence of structure director P123. Pure Pd and Ni NP containing films were also synthesized as controls. Overall a composition of 10 mol% metal (in the case of Pd-Ni, 5 mol% of each metal) and 90 equivalent mol% SiO2 was maintained in the heat-treated films. Grazing incidence X-ray diffraction and transmission electron microscopy studies of the final heat-treated Pd-Ni doped films revealed the (111) oriented growth of the Pd-Ni alloy NPs, with an average size of 5.3 nm, residing inside the mesopores of the SiO2 film. We performed the C-C coupling reaction employing the film-catalysts and the progress of the reaction was monitored using a fluorimeter. Overall, only the Pd-Ni alloy NP doped film showed good catalytic activity with excellent recyclability. It has been determined that the higher oxidising ability of metallic Ni restricted the oxidation of Pd in the Pd-Ni alloy catalyst under the reaction conditions, leading to the maintained reusability in consecutive cycles.

Pd-Ni alloy nanoparticle/carbon nanofiber composites: preparation, structure, and superior electrocatalytic properties for sugar analysis.

Novel Pd-Ni alloy nanoparticle/carbon nanofiber (Pd-Ni/CNF) composites were successfully prepared by a simple method involving electrospinning of precursor polyacrylonitrile/Pd(acac)2/Ni(acac)2 nanofibers, followed by a thermal process to reduce metals and carbonize polyacrylonitrile. The nanostructures of the resulting Pd-Ni/CNF nanocomposites were carefully examined by a combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), high-angle annular dark field (HAADF)-scanning transmission electron microscopy (STEM), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS). For all the nanocomposites, the Pd-Ni alloy nanoparticles (NPs) were dispersed uniformly and embedded firmly within the framework or on the surface of CNF. The size, composition, and alloy homogeneity of the Pd-Ni alloy NPs could be readily tailored by controlling the feed ratio of metal precursors and the thermal treatment process. Cyclic voltammetric studies showed enhanced redox properties for Pd-Ni/CNF-based electrodes relative to the Ni-metal electrode and significantly improved electrocatalytic activity for sugar (e.g., glucose, fructose, sucrose, and maltose) oxidation. The application potential of Pd-Ni/CNF-based electrodes in flow systems for sugars detection was explored. A very low limit of detection for sugars (e.g., 7-20 nM), high resistance to surface fouling, excellent signal stability and reproducibility, and a very wide detection linear range (e.g., 0.03-800 μM) were revealed for this new type of Pd-Ni/CNF nanocomposite as the detecting electrode. Such detection performances of Pd-Ni/CNF-based electrodes are superior to those of state-of-the-art nonenzymatic sugar detectors that are commercially available or known in the literature.

Tandem Dehydrogenation of Ammonia Borane and Hydrogenation of Nitro/Nitrile Compounds Catalyzed by Graphene-Supported NiPd Alloy Nanoparticles

We report a facile synthesis of monodisperse NiPd alloy nanoparticles (NPs) and their assembly on graphene (G) to catalyze the tandem dehydrogenation of ammonia borane (AB) and hydrogenation of R-NO2 and/or R-CN to R-NH2 in aqueous methanol solutions at room temperature. The 3.4 nm NiPd alloy NPs were prepared by coreduction of nickel(II) acetate and palladium(II) acetlyacetonate by borane-tert-butylamine in oleylamine and deposition on G via a solution phase self-assembly process. G-NiPd showed composition-dependent catalysis on the tandem reaction with G-Ni30Pd70 being the most active. A variety of R-NO2 and/or R-CN derivatives were reduced selectively into R-NH2 via G-Ni30Pd70 catalyzed tandem reaction in 5–30 min reaction time with the conversion yields reaching up to 100%. Our study demonstrates a new approach to G-NiPd-catalyzed dehydrogenation of AB and hydrogenation of R-NO2 and R-CN. The G-NiPd NP catalyst is efficient and reusable, and the reaction can be performed in an environment-friendly process with short reaction times and high yields.