Zerovalent Nickel Research Articles

Novel hybrid adsorbent for cationic dye decoloration: Zero-valent nickel nanoparticles supported on activated carbon incorporated in electrospun polyacrylonitrile nanofibers

Novel hybrid adsorbent for cationic dye decoloration: Zero-valent nickel nanoparticles supported on activated carbon incorporated in electrospun polyacrylonitrile nanofibers

Redox transmetallation reaction mediated synthesis of Ni-Pd bimetallic nanocatalyst for pesticide degradation to value added product

In this work a wet-chemical recipe has been accounted for the synthesis of bimetallic Ni-Pd nanostructures at ambient condition involving pre-synthesized nickel nanoparticles and aqueous tetrachloropalladate, [PdCl4]2- solution. The Galvanic replacement reaction (GRR) starts instantaneously between less noble Ni0 nanoparticle i.e., zero valent nickel (ZVN) and more noble [PdCl4]2-. Thus ZVN is oxidatively etched out as soluble Ni2+ by more noble [PdCl4]2- depositing Pd0 onto the residual ZVN. Concurrently the Ni2+ ions move outwardly into the bulk solution and the Pd0enters into the inwardly fashion owing to their different diffusivities and results in the formation of hollow bimetallic nanostructures following diffusion limited nanoscale Kirkendall effect. Finally, the bimetallic nanomaterial was shown to be a competent heterogeneous catalyst for facile hydrolytic degradation of an organothiophosphate pesticide, methyl parathion (MP). After the completion of the degradation, the degraded product, 4-nitrophenolate (4-NP) was subsequently reduced to 4-aminophenolate (4-AP) in the same reaction pot in presence of the same catalyst using borohydride. 4-AP is the principal ingredient for the production of the medicine paracetamol. Hence the bimetallic Ni-Pd nanoparticles turn out to be a promising heterogeneous catalyst for water pollution abatement through pesticide degradation vis-à-vis generation of value added product out of the degraded product of the pesticide.

Highly efficient nickel recovery from industrial wastewater via synergistic electrodeposition and electrocatalytic oxidation technique

This study was conducted to address water pollution concerns entwined with electroless nickel plating (ENP) industry. Its principal endeavor centers on the development and application of an innovative single-compartment technique to proficiently treat spent ENP baths. The research demonstrated the recovery of Nickel (Ni) from wastewater through synergistic interactions between electrocatalytic oxidation and electrodeposition processes. Electrochemical tests used a direct current power supply in constant current mode, with the positive pole on IrO2/Ti mesh and negative pole on stainless steel. Zero-valent nickel recovered on the electrodes was conclusively identified via SEM, XRD, and EDS analyses. This work carefully examined the impact of initial pH, initial Ni ion concentration, and current density (CD) on electrochemical recovery efficiency. The findings suggest that higher current densities positively influence the Ni recovery ratio. Additionally, through meticulous experiments, the viability of this approach for treating spent ENP baths has been confirmed. An impressive 98.88% recovery of Ni was achieved under specific conditions: CD 4.5 mA cm−2, experimental time 180 min, pH 4.5, electrodes spacing 1.5 cm, temperature 55 °C, and a dilution factor 10 times. The study demonstrated the process for Ni recovering from ENP wastewater through direct oxidation and subsequent decomposition, leading to liberation of free Ni ions. The recovered substance, identified as zero-valent nickel, adheres to the electrodes. The method employed in this research is described by its cost-effectiveness, user-friendliness, and low energy consumption. As a result, this study makes valuable contributions to both wastewater remediation and the sustainable utilization of Ni resources.

Performance and mechanism of siderite/zero-valent nickel composite material for removing Se(IV) from solution

79Se is a fission product in spent fuel with a half-life of up to 6.5 × 104 a, which is not controlled by solubility in aqueous solution and has strong mobility. These characteristics make it highly susceptible to migration in groundwater. Meanwhile, due to the negative charge of selenium ions, they are difficult to be fixed by buffer/backfill materials, engineering materials, geological materials and commonly used adsorption methods in near-field geochemical environments. Therefore, the fixation of 79Se has become a hot and difficult research topic both domestically and internationally. Therefore, this article aimed to simulate the removal of radioactive nuclide Se(IV) from high-level radioactive waste disposal repositories. On the basis of siderite (FeCO3), by adding zero-valent nickel (Ni0) and continuously optimizing sample preparation conditions, an economical, efficient and stable siderite/zero-valent nickel (FeCO3/Ni0) composite material was successfully prepared. Experimental studies on the removal of Se(IV) from solution were conducted under different conditions and the material was characterized using various modern methods from macro and micro perspectives, the performance and mechanism of FeCO3/Ni0 composite material for removing Se(IV) was explored deeply. The research results indicated that FeCO3/Ni0 had high potential as a candidate adsorbent for the removal of Se(IV) due to its easy synthesis, low-cost, high adsorption capacity and strong reduction.

Low-cost and highly stable Ni@NC materials synthesized from metal-organic framework precursors for selectively catalytic hydrogenation of p-nitrophenol under mild conditions

The catalytic hydrogenation of aromatic nitro compounds under mild conditions to generate amino compounds is a great challenge in terms of conversion, selectivity and stability. In this paper, two classes of nitrogen-doped carbon coated nickel nanoparticles, coined Ni@NC-P and displaced Ni@NC-T were prepared by high-temperature pyrolysis of MOFs using inexpensive terephthalic acid and high-priced trimesic acid as carbon source, respectively. One from the former class, namely the Ni@NC-P-500 catalyst, exhibits the best catalytic performance, which is superior to Ni@NC-T-500 Samples. For the selective hydrogenation of p-nitrophenol under mild conditions (60 °C, 2 h), the Ni@NC-P-500 catalyst shows >99.9 % conversion of p-nitrophenol and >99.9 % selectivity for p-aminophenol and can be recycled five times without obvious decrease of conversion and selectivity, thanks to its larger specific surface area (382.02 m2·g−1), smaller nickel particle size (8.2 nm), higher nitrogen content (especially pyridine nitrogen), higher electron-rich nickel content and less hydrophilic properties than that of the Ni@NC-T-500. The excellent stability and recyclability of the catalysts are mainly attributed to their core–shell structure, i.e., zero-valent nickel nanoparticles encapsulated within a nitrogen-doped carbon layer with an appropriate microporous structure, whereas zero-valent nickel nanoparticles have the ability to activate dihydrogen and block dioxygen.

CO2 hydrogenation by aqueous NaBH4 solution catalyzed by zero-valent nickel supported on carbon nanofibers

In the reaction system with NaBH4 as a hydrogen donor, inhibiting the formation of hydrogen is the key to promote the efficient catalytic hydrogenation of CO2. In this study, nanoscale zero-valent nickel supported on carbon nanofibers (Ni0/CNFs) was fabricated as a catalyst for CO2 hydrogenation in aqueous NaBH4 solution. The characteristics of Ni0/CNFs were examined. By SEM, it was observed that spherical nickel nanoparticles were distributed homogeneously on the surface of strip-shaped carbon nanofibers. EDS mappings indicated that elements were evenly distributed on the catalyst, which might contribute to the uniform exposure of active sites. Via XRD, it was determined that all the diffraction peaks corresponded to the crystal face of nickel metal and that the absence of diffraction peaks of carbon nanofibers indicated that the crystallinity of the carrier was low. XPS study showed that nickel existed on the catalyst surface in two forms: zero valence metal and oxidation state. The effects of catalyst addition amount, NaBH4 concentration, NaOH dosage, stirring rate on the yield of formate and hydrogen generation rate (HGR) were investigated. By optimizing the above parameters, the concentration of formate reached 150 mmol/L and the hydrogen production rate was 10.55 mL/min. Compared with the non-catalytic conditions, the concentration of formate increased by 57 % and the HGR decreased by 78 %. Moreover, the relationship between CO2 hydrogenation and NaBH4 hydrolysis was clarified. This research could enhance comprehension of CO2 hydrogenation in aqueous NaBH4 solution and contribute to the development of CO2 capture and utilization storage technology. The significance of this study lies in clarifying the connection between CO2 hydrogenation and borohydride hydrolysis in CO2 catalytic hydrogenation technology.

Single-step pyrolysis of biomass waste-derived activated carbon encapsulated zero-valent nickel NPs for the purification of antibiotic-contaminated water

In this study, zero-valent nickel NPs immobilized on biowaste-based activated carbon (ZVNi@AC) were prepared using a single-step pyrolytic reduction/activation method.

Ortho-Fluoro or ortho Effect? Oxidative Addition of Zerovalent Nickel into the C-CN Bond of Substituted Benzonitriles.

A recent study of the oxidative addition of zerovalent Ni to the C-CN bond of F-substituted benzonitriles showed significantly increased stabilization of the C-CN oxidative addition products with o-F groups (-6.6 kcal/mol per o-F) compared to m-F groups (-1.8 kcal/mol per m-F). To answer the question of whether this is an o-F effect or an ortho effect, in this study the effect of CF3 and CH3 groups on the oxidative addition of the [Ni(dmpe)] fragment [dmpe = 1,2-bis(dimethylphosphino)ethane] to the C-CN bond of benzonitriles has been studied. A density functional theory study of the reaction pathway between η2-CN complexes and the C-CN oxidative addition products shows stabilization of the C-CN oxidative addition product with the electron-withdrawing CF3 group and destabilization with the electron-donating CH3 group in both tetrahydrofuran and toluene. There is a slightly larger ortho effect with CF3 (-7.4 kcal/mol) than with F. However, due to steric crowding, two o-CF3 groups did not show considerably more stabilization than one o-CF3 group. There is a linear relationship between ΔG° and the number of meta groups (2.0 kcal/mol stabilization per m-CF3 and 0.8 kcal/mol destabilization per m-CH3). On the basis of natural population analysis, as the C-CN bond becomes more polarized, the stability of the C-CN oxidative addition products with respect to the η2-CN complexes increases.

Carbon-based heterostructure from multi-photo-active nanobuilding blocks SrTiO3@NiFe2O4@Fe0@Ni0@CNTs with derived nanoreaction metallic clusters for enhanced solar light-driven photodegradation of harmful antibiotics

We reported on the sequential development of a high-operative photocatalyst with penta-component inorganic bulk heterojunction for improved charge trapping characteristics at particle–particle interfaces for enhanced solar light-driven photocatalytic degradation of active tetracycline antibiotic. Structural, morphological, optical, and electronic properties of the synthesized samples were investigated using a series of complementary characterization techniques, such as XRD, FE-SEM, HR-TEM, XPS, as well as hard and soft XAS in both total electron yield (TEY) and fluorescence yield (TFY). For the case of the carbon composite material, SrTiO3@NiFe2O4@Fe0@Ni0@CNTs, a reduced crystallinity when compared to the starting support material was noticed, although this translated into a significant improvement of the morphology and the photocatalytic performance. The SrTiO3@NiFe2O4@Fe0@Ni0@CNTs fibrous photocatalyst can efficiently achieve a high-to-total degradation of tetracycline antibiotic under visible light irradiation in less than two hours, following a non-linear PFO kinetic model with an apparent reaction rate of about 0.0606 min−1 and an 98% photodegradation activity. The XPS and XAS analysis demonstrated unequivocally the appearance of nanoscale zero-valent iron (Fe0) and zero-valent nickel (Ni0) on the photocatalyst surface, which facilitates the separation of photogenerated e+ and h+ pairs, and the appearance of more active sites.

Recovery of nickel from actual electroplating wastewater by integrated electrodeposition with adsorption pretreatment technique

The rapidly growing electroplating industry has led to the discharge of large amounts of wastewater containing heavy metals. Electrodeposition technique can recover metals from wastewater, however, its application involves high energy costs due to the high levels of inorganic and organic impurities, including metal ions, that are usually present in real effluents. Therefore, in the present work, integrated electrodeposition with adsorption pretreatment technique was employed to recover nickel from real electroplating wastewater in a cost-effective manner. The results showed that adsorption pretreatment technique could simplify the nature of the wastewater by removing 85% of TOC from real electroplating wastewater. Further, the pretreated wastewater was used for electrodeposition and the results indicated that the electrodeposition could reduce the ineffective energy consumption by 50% (from 44 kw∙h/kg to 35 kw∙h/kg) for actual wastewater, compared to the effective energy consumption of 28 kw∙h/kg for simulated wastewater which hinted that the pretreatment by adsorption technique had a positive effect on the deposition of nickel. Analysis of the deposits showed that the recovered nickel was mainly in the form of zero-valent nickel or oxides. The zero-valent nickel adhered tightly to the electrode plates, while the oxide form mainly adhered to the electrode plates or fell off into the electrolyte. Importantly, the findings of EDS and XRD showed that both simulated and actual wastewater yielded high-purity metallic nickel. Overall, this work provided an effective way to promote the application of integrated electrodeposition with adsorption pretreatment technique for the recovery of precious metals from real electroplating wastewater.

Core-shell structured Fe/Ni@C ternary micro-electrolysis material for 4-nitrochlorobenzen removal: Performance assessment and mechanism insight

In this work, core-shell iron/nickel@carbon (Fe/Ni@C) and conventional supported iron/nickel-carbon (Fe/Ni-AC) ternary micro-electrolysis materials were synthesized and utilized for the removal of 4-nitrochlorobenzene (4-NCB). The characterization of Fe/Ni@C were preliminarily investigated and compared with Fe/Ni-AC to highlight its superiority and feasibility in contaminants degradation. Results indicated that Fe/Ni@C with the core-shell structure possessed a higher oxidation resistance, electron transfer ability and oxygen utilization capacity. The degradation efficiency of 4-NCB was appreciably more significant than that of the Fe/Ni-AC system under diverse aeration conditions. This mainly was ascribed to the core-shell structure which reinforced the connection of dual-cathodes and anode and shortened the distance between zero-valent iron (Fe0) and zero-valent nickel (Ni0) for intensified electrons transfer. Electrons donated from Fe0 could enrich in high density on the surface of carbon. This high-density electronic release, on the one hand, could significantly promote the reduction of pollutants under N2. On the other hand, this enrichment realized the synergetic effect of reduction and oxidation in the absence of dissolved oxygen (DO). By combining the analysis of reduction intermediates, reactive oxidizing species and XPS, the reaction mechanisms of Fe/Ni@C under diverse aeration conditions were explored in-depth. These findings can contribute to the rational design of ternary micro-electrolysis systems with properties tailored to a variety of nitroaromatic organics in natural water remediation.

In situ synthesis, crystal structure, selective anticancer and proapoptotic activity of complexes isolated from the system containing zerovalent nickel and pyrazole derivatives

New nickel(II) complexes [NiLS(NCS)2]∙CH3CN (1) [Ni(dmpz)2(NCS)2]n (2), where LS is N,N,N-tris(1-(3,5-dimethylpyrazolylmethyl)amine) and dmpz is 3,5-dimethylpyrazole, have been isolated in a one-pot synthesis by reacting zerovalent-powered nickel, 1-hydroxymethyl-3,5-dimethylpyrazole (HL1) and 1-carboxamide-3,5-dimethylpyrazole (HL2) as precursors. The complexes were characterized by elemental analysis, IR and UV–Vis spectra, thermal investigations and single crystal diffraction studies. The anti-proliferative activity of the described Ni(II) complexes was studied in vitro against selected human tumour cell lines and normal human cells (fibroblasts). The monomeric complex [NiLS(NCS)2]∙CH3CN (1) expressed more potent anti-proliferative activity towards cancer cells with the relevant cytotoxicity, while the polymeric complex [Ni(dmpz)2(NCS)2]n (2) was very toxic towards normal cells and was also characterized by mild inhibitory potency against tumour cells and poor selectivity. Complex (1) causes massive death of cancer cells due to programmed cell death, apoptosis. The obtained results demonstrated potent cytotoxic activity of the isolated [NiLS(NCS)2]∙CH3CN complex combined with strong selectivity towards cancer cells, and the mechanism of its actions included apoptosis.

Modification of structured bio‑carbon derived from spongin-based scaffolds with nickel compounds to produce a functional catalyst for reduction and oxidation reactions: Potential for use in environmental protection

Three different 3D fibrous-like NiO/Ni(OH)2/Ni‑carbonized spongin-based materials were prepared via a simple sorption–reduction method. Depending on the support used, the catalysts were composed of carbon, nickel oxide, nickel hydroxide and zero-valent nickel, with the surface content of the nickel-containing phase in the range 15.2–26.0 wt%. Catalytic studies showed promising activity in the oxidation of phenolic compounds in water and in the reduction of 4-nitrophenol. The oxidation efficiency depends on the substrate used and ranges from 80% for phenol at pH 2 to 99% for 4-chlorophenoxyacetic acid (4-CPA) and methylchlorophenoxypropionic acid (MCPP). In the reduction reaction, all catalysts exhibited superior activity, with rate constants in the range 0.648–1.022 min-1. The work also includes a detailed investigation of reusability and kinetic studies.

Aufbau‐ und Abbaureaktionen von weißem Phosphor induziert durch N‐heterocyclische Carbenkomplexe von Nickel(0)

AbstractDie Reaktion von Nickel(0)‐Verbindungen mit weißem Phosphor (P4) ist eine kaum erforschte Syntheseroute für binäre Nickelphosphidcluster. Wir zeigen, dass die Reaktion von P4 mit koordinativ und elektronisch ungesättigten N‐heterocyclischen Carbenkomplexen von Nickel(0) die Darstellung ungewöhnlicher Clusterverbindungen mit P1‐, P3‐, P5‐ und P8‐Einheiten ermöglicht. Die Verwendung von [Ni(IMes)2] [IMes=1,3‐Bis(2,4,6‐trimethylphenyl)imidazolin‐2‐yliden] führt zu Spezies mit Ni3P4‐ und Ni3P6 Gerüst, die als superhypercloso‐ bzw. hypercloso‐Cluster beschrieben werden können. Komplexe mit sterisch anspruchsvolleren Carbenliganden [Ni(IPr)2] bzw. [(IPr)Ni(η6‐Toluol) [IPr=1,3‐Bis(2,6‐diisopropylphenyl)imidazolin‐2‐yliden] führen hingegen zur Synthese eines closo‐Ni3P8‐Clusters. Die inversen Sandwichkomplexe [(NHC)2Ni2P5] (NHC=IMes, IPr) mit einem aromatischen cyclo‐P5−‐Liganden wurden als weitere Reaktionsprodukte identifiziert.

Aggregation and Degradation of White Phosphorus Mediated by N-Heterocyclic Carbene Nickel(0) Complexes.

The reaction of zerovalent nickel compounds with white phosphorus (P4) is a barely explored route to binary nickel phosphide clusters. Here, we show that coordinatively and electronically unsaturated N‐heterocyclic carbene (NHC) nickel(0) complexes afford unusual cluster compounds with P1, P3, P5 and P8 units. Using [Ni(IMes)2] [IMes=1,3‐bis(2,4,6‐trimethylphenyl)imidazolin‐2‐ylidene], electron‐deficient Ni3P4 and Ni3P6 clusters have been isolated, which can be described as superhypercloso and hypercloso clusters according to the Wade–Mingos rules. Use of the bulkier NHC complexes [Ni(IPr)2] or [(IPr)Ni(η6‐toluene)] [IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene] affords a closo‐Ni3P8 cluster. Inverse‐sandwich complexes [(NHC)2Ni2P5] (NHC=IMes, IPr) with an aromatic cyclo‐P5 − ligand were identified as additional products.

Nano scale zerovalent nickel: Green synthesis, characterization, and efficient removal of lead from aqueous solution

Lead is one of the toxic heavy metal pollutants and if present in water above its permissible limit can lead to various neurodevelopmental and cardiovascular disorders in human beings. The objective of the present work is removal lead ions from aqueous solution using novel nickel nanoparticles (AONi) prepared by green synthesis from testa extract of Annacardium occidentale which acts as an eco-friendly adsorbent. The physicochemical properties of AONi nanoparticles were characterized through UV-Visible spectroscopy, FTIR analysis, SEM-EDS, XRD, and HR-TEM analysis. The adsorption capacity of AONi nanoparticles and the effect of pH, adsorbent and adsorbate dosage, and contact time are studied by batch experiments and analyzed by Langmuir and Freundlich adsorption isotherm. The correlation coefficient, R2 = 0.99 is in agreement with Freundlich’s multilayer adsorption. The separation factor, RL of Langmuir isotherm is 0.20, which also indicates favorable adsorption. Kinetic studies further confirm that the adsorption follows a pseudo-second-order mechanism.

Zerovalent nickel nanoparticles performance towards Cr(VI) adsorption in polluted water

Heavy metals are one of the most common types of pollutants in ground water due to their wide sources, non-degradability and high toxicity. Many traditional wastewater treatments were not capable of removing enough such contaminants in order to meet quality standards. Nanosized zerovalent transition metals have emerged as a great candidate for ground water remediation, due to their simplicity and low fabrication cost, furthermore they can comply with simple chemical synthesis. Here, we present the synthesis of nano zerovalent nickel (nZVN) by a simple grinding reduction method. The obtained nZVN was characterized with XRD, SEM, EDS and BET surface area. The results confirms the formation of nZVN and the active particle cluster size ranges from 100 to 200 nm. N2 adsorption isotherms revealed that the formation mesoporous cluster of nZVN with good surface area. The adsorption of Cr(VI) using nZVN showed 96% removal efficiency for 10 ppm concentration, and even up to 98% when the temperature is slightly raised to 36 °C (309 K). The removal efficiencies of Cr by zerovalent nickel was well fitted by the Langmuir–Hinshelwood first order reaction kinetic model with deceptive rate constant values of 0.6699, 0.7956 and 1.0251 min−1 at temperature 200, 303 and 309 K, respectively. In total, our studies suggest that nanoscale zerovalent iron is a capable material for Cr(VI) remediation from groundwater.

Kinetics and isothermal adsorption of U(VI) in aqueous solution by nano-Ni0

The nanoscale zero-valent nickel (nano-Ni0) was prepared by liquid-phase reduction method and characterized by BET, XPS, FT-IR and XRD and be used to remove U(VI) from aqueous solution. The data were analyzed by the Langmuir and Freundlich models. The kinetic data were analyzed by pseudo-first-order kinetic and pseudo-second-order models. The results showed that the nano-Ni0 had a good removal efficient on U(VI), after reaction, the peaks of Ni2+ and U4+ appeared in XPS spectra, which revealed that the U(VI) was reduced to U(IV) and Ni0 was oxidated to Ni2+ and Ni3+. The kinetics and isothermal models showed that the adsorption process was surface monolayer adsorption and was controlled by chemical adsorption rate.

Stereoelectronic Properties of 1,2,4-Triazole-Derived N-heterocyclic Carbenes - A Theoretical Study

Stereoelectronic Properties of 1,2,4-Triazole-Derived N-heterocyclic Carbenes - A Theoretical Study

Tris(butadiene) Metal Complexes of the First-Row Transition Metals versus Coupling of Butadiene to Eight- and Twelve-Carbon Hydrocarbon Chains.

The role that zerovalent nickel plays in catalyzing the trimerization of butadiene to 1,5,9-cyclododecatriene conveys interest in the properties of the tris(butadiene)metal complexes (C4H6)3M. In this connection the complexes (C4H6)3M (M = Ti-Ni) of the first-row transition metals have been investigated by density functional theory. The intermediate C12H18Ni which has been isolated in the nickel-catalyzed trimerization of butadiene but is too unstable for X-ray crystallography is suggested here to have an open-chain hexahapto η3,3-C12H18 ligand rather than the octahapto such ligand suggested by some investigators. The lowest energy (C4H6)3M structures of the other first-row transition metals from vanadium to cobalt are found to have related structures with open-chain C12H18 ligands having hapticities ranging from four to eight with hexahapto structures being most common. The nickel and cobalt (C12H18)M derivatives favor low-spin singlet and doublet spin states, respectively, whereas the manganese derivative (C12H18)Mn favors the high-spin sextet state corresponding to the half-filled d5 shell of Mn(II). A (C4H6)3Cr structure with three separate tetrahapto butadiene ligands analogous to the very stable (η4-C4H6)3M (M = Mo, W) with the favored 18-electron metal configuration is found to be a very high energy structure relative to isomers containing an open-chain C12H18 ligand.