Supported Nickel Nanoparticles Research Articles

Supported Nickel Nanoparticles as Catalyst in Direct sp3 C-H Alkylation of 9H-Fluorene Using Alcohols as Alkylating Agent.

Herein, we report an inexpensive first-row transition metal Ni heterogeneous catalytic system for the Csp3-mono alkylation of fluorene using alcohols as alkylating agents via borrowing hydrogen strategy. The catalytic protocol displayed versatility with high yields of the desired products using various types of primary alcohols, including aryl/hetero aryl methanols, and aliphatic alcohols as alkylating agents. The catalyst Ni NPs@N-C was synthesized via high-temperature pyrolysis strategy, using ZIF-8 as the sacrificial template. The Ni NPs@N-C catalyst was characterized by XPS, HR-TEM, HAADF-STEM, XRD and ICP-MS. The catalyst is stable even in the air at room temperature, displayed excellent activity and could be recycled 5 times without appreciable loss in its activity.

Interplay Between Ni and Brønsted and Lewis Acid Sites in the Hydrodesulfurization of Dibenzothiophene.

Ni-MoS2/γ-Al2O3 catalysts are commonly used in hydrotreating to enhance fossil fuel quality. The extensive research on these catalysts reveals a gap in understanding the role of Ni, often underestimated as an inactive sulfide phase or just a MoS2 promoter. In this work, we focused on analyzing whether well-dispersed supported nickel nanoparticles can be active in the hydrodesulfurization of dibenzothiophene. We dispersed Ni by Strong Electrostatic Adsorption (SEA) method across four supports with different types of acidity: silica (~ neutral acidity), γ-Al2O3 (Lewis acidity), H+-Y zeolite, and microporous-mesoporous H+-Y zeolite (both with Brønsted-Lewis acidity). Our findings reveal that Ni is indeed active in dibenzothiophene hydrodesulfurization, even with alumina and silica as supports, although their catalytic activity declines abruptly in the first hours. Contrastingly, the acid nature of zeolites imparts sustained stability and performance, attributed to robust metal-support interactions. The efficacy of the SEA method and the added mesoporosity in zeolites further amplify catalytic efficiency. Overall, we demonstrate that Ni nanoparticles may perform as a hydrogenating metal in the same manner as noble metals such as Pt and Pd perform in hydrodesulfurization. We discuss some of the probable reasons for such performance and remark on the role of Ni in hydrotreatment.

The crucial role of casein on crystal structure, size, morphology, and magnetic properties of carbon supported Ni nanoparticles

Carbon supported nonprecious metal nanoparticles have gained significant attention for their low cost and excellent properties. However, immobilizing them with good dispersion on carbon supports is still a great challenge. Herein, we report a simple and low cost thermal decomposition method to prepare a high quality carbon supported nickel nanoparticles in presence of casein as carbon source. By optimizing the concentration of carbon source, engineered the particle size from 50 nm to 17 nm and morphology from pyramid to spherical. Further, the impacts of morphology and particle size on the magnetic properties of these nanoparticles are studied. Moreover, thermally stable, biocompatible, low cost with unique magnetic properties makes these materials as potential candidate for various applications including chemisorbers, sensor, and electrochemical uses.

Stable and selective multi-porous nickel nanoparticles catalysts for hydrocracking of dibenzyl ether supported by DFT studies

Preparation of clean fuel from biomass has a crucial significance on the development and utilization of renewable clean energy. In this study, a multi-stage porous mordenite supported nickel nanoparticles catalyst (Nix%/HMOR) was prepared, which showed that its acid content, acidity, porosity, specific surface area and metal dispersion were significantly improved while the crystallization strength was basically the same compared with microporous mordenite. In order to study the conversion mechanism of biomass energy, dibenzyl ether was selected as a typical lignin model compound. Under the condition of Ni10%/HMOR in n-hexane at 160 °C for 2 h under 5 MPa of initial hydrogen pressure, the conversion of dibenzyl ether was 100 % and the selectivity of methyl cyclohexane was 84.4 %, which manifested that Ni10%/HMOR had good activity in the selective hydrocracking process under mild conditions. Furthermore, density functional theory (DFT) was selected to study the activation energies of different reaction sites on dibenzyl ether bridge bonds and the recombination process of free radicals in the reaction process. It comes to a conclusion that the O atom on the C-O bridge bond is easier to be attacked by H*, and the C-O bond of the unsaturated aromatic ring is easier to break. During the recombination of free radicals, the two C-O bond breaking energy barriers of OMD are different, and H free radicals are more likely to attack the O atom in cyclohexane-methanol. It is conducive to the formation of stable compound 1 - (cyclohexylmethyl) − 1-methylcyclohexane and its isomers.

Ceria supported nickel nanoparticles for catalytic hydroconversion of lignin-related model compounds

The combination method of impregnation, desiccation, and subsequent reduction with H2 was applied to prepare Nix/CeO2. Each catalyst was characterized with multiple tools and its catalytic performance for the catalytic hydroconversion (CHC) of lignin-related model compounds (LRMCs) containing oxybis(methylene)dibenzene (OBMDB) and guaiacol was evaluated. Over Ni14%/CeO2, OBMDB was completely converted into methylcyclohexane under initial hydrogen pressure (IHP) of 3 MPa at 200 °C for 2 h. The complete conversion of guaiacol to cyclohexanol (CHII) was realized under IHP of 4 MPa at 200 °C for 3 h. Additionally, H2 can be activated to H⋯H, H+, and H− over Ni14%/CeO2. H+ is attracted by oxygen atom in OBMDB, leading to the cleavage of >CH2-O- bond to produce phenylmethanol (PM) and benzylium, which is subsequently comminated with H− to produce toluene. Next, H⋯H transfers to toluene and PM resulting in the hydrogenation of benzene rings (BRs) to produce methylcyclohexane and cyclohexylmethanol followed by the dehydration to form methylcyclohexane. BR in guaiacol was hydrogenated by H⋯H transfer to produce 2-methoxycyclohexan-1-one (MCHI) and 2-methoxycyclohexan-1-ol (MCHII) in sequence and subsequent demethoxylation of them to generate cyclohexanone (CHI) and CHII, respectively. Finally, H⋯H transfers to CHI to produce CHII.

Chitosan/hybrid ceria supported nickel nanoparticles: Study of magnetic and optical properties, photodegradation of rhodamine B, and antimicrobial activity, with DFT

In this study, we explore the magnetic and optical properties of nickel nanoparticles decorated with chitosan/hybrid ceria (iron doped ceria) alongside their potential use in the photodegradation of rhodamine B dye. To support our experimental results, we use Density Functional Theory (DFT) analysis. In addition, the antibacterial activity of the synthesized nanocomposite is evaluated. The hybrid nanoparticles have interesting magnetic and optical characteristics, which make them a viable option for a variety of applications. The chitosan hybrid ceria-nickel nanoparticles also successfully photodegrade the dye rhodamine B, suggesting their potential uses in environmental remediation. Additionally, the nanocomposite antimicrobial activity against the gram-positive Streptococcus pneumoniae and gram-negative Klebsiella pneumonia, which cause a variety of diseases including pneumonia, urinary tract infection, sinusitis, osteomyelitis, meningitis, and septic arthritis, was evaluated demonstrating the nanocomposite ability to fight infectious infections. Overall, this paper thoroughly evaluates the nickel nanoparticles supported on the chitosan hybrid ceria, emphasizing their various features and prospective uses.

Cobalt hydroxide supported nickel nanoparticles for an efficient electrocatalytic urea oxidation reaction

An efficient electrochemical urea oxidation reaction (UOR) could be used in energy production technology. Metallic nickel nano-particles (Ni NPs) are incorporated in cobalt hydroxide layered material to form Ni/Co(OH)2. The synthesized material is utilized as an electrocatalyst in UOR. It has been revealed that the incorporation of Ni NPs into cobalt hydroxide significantly enhances their electrocatalytic activity toward UOR. Ni/Co(OH)2 catalyzes UOR at a very low anodic potential of 1.15 V vs RHE with a peak current density of 14.2 mAcm−2 and Tafel slope of 75 mVdec−1. The current work is a step ahead towards use of transition metal hydroxide (TMH) as support in the electrocatalytic oxidation applications especially UOR.

Efficient hydrogenation of N-heteroarenes into N-heterocycles over MOF-derived CeO2 supported nickel nanoparticles

The selective hydrogenation of N-heteroarenes into N-heterocycles is a highly important organic transformation in fine chemical industry, as N-heterocycles are moieties in a variety of pharmaceutical and bioactive compounds. Here, we report highly efficient mesoporous CeO2 supported Ni catalysts prepared by the incipient wet impregnation and following high-temperature reduction for the selective hydrogenation of N-heteroarenes. The experiments indicated that the synergistic effect between CeO2 and Ni nanoparticles was responsible to the superior catalytic performance. Various kinds of N-heterocycles were obtained at 120 °C with yields of 86 ∼ >99%, demonstrating the versatility of the developed method. This work is valuable for guiding the design and manipulation of low metal loading, cost-effective and robust hydrogenation catalysts.

Effect of Ni NP morphology on catalyst performance in non-thermal plasma-assisted dry reforming of methane

Supported nickel nanoparticle catalysts, with differing nickel morphologies, were studied in the non-thermal-plasma-promoted dry reforming of methane. Catalysts with nickel particles containing a greater ratio of (111) lattice planes and surface structures in the nanoscale, i.e. dendritic and flake-like particles, showed higher conversions and yields (CH4 conversions of 65 % and 22 % and CO2 conversions of 43 % and 33 % respectively with H2 yields of 42 % and 34 % and CO yields of 31 % and 24 % respectively) than spherical analogues which had conversions of 26 % (CH4) and 16 % (CO2) and yields of 21 % (H2) and 11 % (CO). This is thought to be related to the favourability of (111) faces for CH4 dissociation and the potential for the formation of micro-discharges around their small surface features. All materials tested showed higher CH4 conversion and H2 production when compared with reactions carried out in the absence of a catalyst. The latter reactions showed a greater extent of competing side reactions, resulting in lower conversions and yields.

Rational design of hollow nitrogen-doped carbon supported nickel nanoparticles for efficient electrocatalytic CO2 reduction

Electrocatalytic carbon dioxide reduction reaction (CO2RR) is a promising approach to achieving a carbon-neutral cycle and producing valuable fuels and chemicals. Herein, we develop a nickel nanoparticle embedded in a hollow nitrogen-doped carbon (Ni@HNC) catalyst with the optimum carbon oxide (CO) Faradaic efficiency of 93.3% at − 0.79 V versus reversible hydrogen electrode (vs. RHE). A series of controlled experiments demonstrated that the PDA-assisted derivatized hollow nitrogen-doped carbon support facilitates the diffusion of CO2 molecules. As proton acceptors, the nickel active sites promote the proton-coupled electron transport process of electroreduction of CO2 to CO. Additionally, Ni@HNC was performed as a bifunctional catalyst, and the coupled anodic methanol oxidation reaction (MOR) can significantly reduce the voltage, about 424 mV at 10 mA cm-2 (versus oxygen evolution reaction, OER). For a two-electrode system, the Faradaic efficiency of CO was maintained above 85% at a wide voltage window (2.1 ∼ 3.1 V), with a maximum value of 98.7% at 2.7 V and a current density of 11.14 mA cm-2. This work provides an efficient strategy to obtain lower CO2RR voltage while acquiring high value-added formate from the anode.

Magnetically Induced CO2 Methanation In Continuous Flow Over Supported Nickel Catalysts with Improved Energy Efficiency.

A new selective and efficient catalytic system for magnetically induced catalytic CO2 methanation was developed, composed of an abundant iron-based heating agent, namely a commercial iron wool, combined with supported Nickel nanoparticles (Ni NPs) as catalysts. The effect of metal oxide support was evaluated by preparing different 10 wt % Ni catalyst (TiO2 , ZrO2 , CeO2 , and CeZrO2 ) via organometallic decomposition route. As-prepared catalysts were thoroughly characterized using powder X-ray diffraction, electron microscopy, elemental analysis, vibrating sample magnetometer, and X-ray photoelectron spectroscopy techniques. High conversion and selectivity toward methane were observed at mid-temperature range, hence improving energy efficiency of the process with respect to the previous results under magnetic heating conditions. To gain further insight into the catalytic system, the effects of the synthesis method and of 0.5 wt % Ru doping were evaluated. Finally, the dynamic nature of magnetically induced heating was demonstrated through fast stop-and-go experiments, proving the suitability of this technology for the storage of intermittent renewable energy through P2G process.

Particle Size Effects of Carbon Supported Nickel Nanoparticles for High Pressure CO2 Methanation

AbstractSupported nickel nanoparticles are promising catalysts for the methanation of CO2. The role of nickel particle size on activity and selectivity in this reaction is a matter of debate. We present a study of metal particle size effects on catalytic stability, activity and selectivity, using nickel on graphitic carbon catalysts. Increasing the Ni particle size from 4 to 8 nm led to a higher catalytic activity, both per gram of nickel and normalized surface area. However, the apparent activation energy remained the same (∼105 kJ mol−1). Comparing experiments at atmospheric to 30 bar pressure demonstrates the importance of testing under industrially relevant pressures; the highest selectivity is obtained at high CO2 conversions and pressures. Finally, the selectivity was particle size‐dependent. The largest particles were not only most active but also most selective to methane. With this work we contribute to the ongoing debate about Ni particle size effects in CO2 methanation.

Phosphorous‐modified Porous Carbon Supported Nickel Nanoparticles as a Catalyst for the Reduction of Nitroaromatics in Water

AbstractPhosphorus‐modified porous carbon (PCP) with about 7 w% phosphorus content has been prepared from acetylene and triphenylphosphine using chemical vapor deposition method. Then, 5, 10, 15, 20, 25, and 30 w% nickel(0) nanoparticles have been deposited (using the in‐situ reduction of NiCl2 salt) on the surface of PCP to obtain Ni‐decorated PCP (NPCP). The prepared materials (NPCP) have been employed as a catalyst for the catalytic reduction of nitrobenzene derivatives to anilines. The NPCP with 20 w% of Ni showed the highest catalytic efficiency. The reaction was carried out using 10 mg catalyst, 2 mL of 25 % hydrazine hydrate solution as the reducing agent in 2 h (optimized conditions) to obtain the product in 51–100 % yield. To show the versatility of this method, 8 nitrobenzene derivatives (including 3 different nitrophenols) have been successfully reduced using this method. The recyclability of the catalyst was investigated and the results showed only 20 % decreasing in the yield after 6 runs.

Boron nitride supported nickel nanoparticles as catalyst for enhancing the hydrogen storage properties of MgH2

In this work, layered boron nitride nanosheets loaded with fine nickel particles were synthesized by a solution chemical reduction method and introduced into MgH2. The best catalytic activity in kinetics has been found in Ni70 @BN, the nickel particles of which are only 10–30 nm in size, showing homogenous dispersion state. Ni particles distributed on the surface of BN provided many active sites, which markedly improved the hydrogen storage properties of MgH2. The MgH2/Ni70 @BN composite absorbs 5.34 wt% H2 swiftly within 25 s at 125 °C and releases 6.21 wt% H2 in 15 min at 300 °C. The dehydrogenation activation energy is reduced to 59.77 ± 3.96 kJ/mol, which is significantly lower than that of pure MgH2 (145.08 kJ/mol). Moreover, BN acts as the aggregation preventer, thereby maintaining outstanding cycling performance of Ni70 @BN modified MgH2 even after 30 cycles. According to DFT calculations, the in-situ formed Mg2Ni is verified to reduce the barrier energy of (de)hydrogenation. Thus, the synergistic effect between BN and Mg2Ni(H4) facilitates the “hydrogen pump” effect to accelerate the ad/desorption kinetics of Mg/MgH2. This work will attract more attention to the synergistic effect of 0D and 2D structures and supplies a new insight into the design of multi-phase catalysts.

Effective hydroconversion of heteroatom-containing organic species from the extraction of low-temperature coal tar to cycloalkanes over a Y/Beta composite zeolite supported nickel nanoparticles

The preparation of high activity bifunctional catalysts, especially hierarchical porous zeolite-supported metal catalysts, are of great important for efficient converting the heteroatom-containing organic species to high quality clean fuels. An excellent performance Ni catalyst was prepared by loading highly dispersed Ni nanoparticles (NNPs, ca. 10%) on Y/Beta composite zeolite (YBCZ) and denoted as Ni10%/YBCZ. Low-temperature coal tar was efficiently extracted with petroleum ether, methanol, and carbon disulfide (CDS) at room temperature under ultrasonic irradiation to obtain CDS extractable portion (EPCDS) in the yield of 20.1%. According to the analysis with a GC/MS, EPCDS consists of chain alkanes (CAs, 4.0%), oxygen-containing organic compounds (OCOCs, 56.0%), arenes (35.3%), nitrogen-containing organic compounds (NCOCs, 3.3%), and sulfur-containing organic compounds (SCOCs, 1.4%). It was subjected to catalytic hydroconversion (CHC) over Ni10%/YBCZ at 160 °C for 18 h under 5 MPa of initial hydrogen pressure to obtain EPCHC. The results show that all organic species in EPCDS were completely converted to CAs (9.0%), cycloalkanes (70.8%), and hydroarenes (20.2%). In Ni10%/YBCZ, hierarchical porous zeolite-zeolite composite with strong Lewis acid sites in its crystal texture and highly dispersed NNPs play crucial roles in removing heteroatoms and hydrogenating aromatic rings, respectively. Oxydibenzene, a model compound with > Car-O bridge bonds and aromatic rings, was used to investigate the catalytic activity of Ni10%/YBCZ. Oxydibenzene was effectively converted to cyclohexane, bicyclohexane, and tercyclohexane over Ni10%/YBCZ in n-pentane at 160 °C for 2 h under 5 MPa of initial hydrogen pressure, indicating that Ni10%/YBCZ has excellent activity in CHC process under mild conditions.

Lignin@Ni‐NPs: A Novel, Highly Efficient, Recyclable, and Selective Nanocatalyst for Base‐Free Transfer Hydrogenation Reactions at Room Temperature

AbstractNickel nanoparticles were synthesized readily by sonication of a mixture of nickel(II) chloride hexahydrate, hydrazine hydrate, lignin and water at 60 °C. This lignin supported nickel nanoparticles (Lignin@Ni‐NPs) have been characterized by UV‐Visible, PXRD, EDX, SEM and TEM techniques. The average size of Ni‐NPs was found in the range of 15‐20 nm as revealed by TEM micrographs. The amount of nickel(0) loaded in Lignin@Ni‐NPs determined by EDX was 36.6 %. The catalytic activity of Lignin@Ni‐NPs have been evaluated in the transfer hydrogenation of carbonyl compounds into the corresponding alcohols. The catalyst have been found efficient for hydrogen‐transfer reduction of functionalised and non‐fuctionalised including heteroaromatic carbonyl compounds as the desired alcohols were obtained in high yields of about 90‐95 % at room temperature, under base‐free conditions and in short reaction times. The catalyst was recovered by simple filtration and it has an advantage of being reuable more than six times without significant loss in its catalytic activity.

Oxidation of Supported Nickel Nanoparticles at Low Exposure to O2: Charging Effects and Selective Surface Activity.

The oxidation of Ni nanoparticles supported on highly oriented pyrolytic graphite was investigated under conditions of low exposure to oxygen by methods of scanning tunneling microscopy and spectroscopy. It was found that charge transfer effects at the Ni-C interface influenced the surface activity of the nanoparticles. The O2 dissociation and the Ni oxidation were shown to occur only at the top of the nanoparticle, while the border of the Ni-C interface was the less preferable area for these processes. The O2 dissociation was inhibited, and atomic oxygen diffusion was suppressed in the given nanosystem, due to the decrease in holes concentration.

Boron Nitride Supported Nickel Nanoparticles as Catalyst for Enhancing the Hydrogen Storage Properties of Mgh2

Boron Nitride Supported Nickel Nanoparticles as Catalyst for Enhancing the Hydrogen Storage Properties of Mgh2

Nitrogen-doped porous carbon supported nickel nanoparticles as catalyst for catalytic hydroconversion of high-temperature coal tar

A novel and highly active nitrogen-doped porous carbon-supported nickel catalyst Ni@N-PC was successfully developed by a thermolysis of nickel-based zeolitic imidazolate frameworks growing on both sides of graphitic carbon nitride and used for catalyzing hydroconversion of isopropanol soluble portion from ultrasonic extraction of high-temperature coal tar (ISPHTCT). The active nickel nanoparticles were mainly encapsulated on the top of carbon nanotubes and partially dispersed on the surface of carbon nanosheets. Naphthalen-1-ol was used as a model compound to investigate the catalytic hydroconversion activity under different reaction conditions and reveal the mechanism for catalytic hydroconversion. The ISPHTCT and catalytic hydroconversion products of ISPHTCT (ISPCHCP) were analyzed with gas chromatograph/mass spectrometer. The results show that 70% of naphthalen-1-ol was converted at 160°C and completely converted at 200°C for 120 min, and the ISPHTCT was greatly upgraded. A total of 180 organic compounds including 33 nitrogen-containing organic compounds, 11 sulfur-containing organic compounds and 39 oxygenates were identified in ISPHTCT, while no obvious nitrogen-containing organic compounds, sulfur-containing organic compounds and oxygenates were detected in ISPCHCP, indicating the excellent performance of Ni@N-PC for heteroatom removal. All the alkenes, cyclenes and alkynes were saturated and the majority of arenes were converted to cyclanes by catalytic hydroconversion over Ni@N-PC, which exhibited high catalytic hydrogenation activity.

Synthesis of sawdust carbon supported nickel nanoparticles and its application in upgrading heavy crude oil

Nickel nanoparticles was supported on sawdust carbon via a hydrothermal method followed by calcination and used as a catalyst for heavy crude oil upgrading experiment. The performance of catalyst on catalytic pyrolysis of heavy crude oil was studied by laboratory experiments. The experimental results showed that under the reaction conditions of 350 °C, 30 min and 0.1 wt% catalyst, the viscosity reduction ratio of heavy crude oil was 74.50%, the viscosity can be reduced from 16,000 mPa·s (50 °C) to 4080 mPa·s, and the net efficiency of catalyst was 14.37%. Analysis results suggested that the viscosity reduction of heavy crude oil was caused by the destruction of structure of resin in the process of the catalytic pyrolysis reaction.