Ni NPs Research Articles

Erratum: Acceptorless Dehydrogenation under Neat Reaction Conditions: Synthesis of 2-Aryl/Alkyl Quinazolinones Using Supported Ni NPs as Catalyst

Erratum: Acceptorless Dehydrogenation under Neat Reaction Conditions: Synthesis of 2-Aryl/Alkyl Quinazolinones Using Supported Ni NPs as Catalyst

Highly stable and electron-rich Ni single atom catalyst for directed electroreduction of CO2 to CO

Transition metal-nitrogen-carbon (M−N−C) are considered as promising candidates for the electrochemical conversion of inert CO2 into high value-added CO products. However, previous reports have focused on Ni single-atom sites (Ni SAs) and the role of Ni nanoparticles (Ni NPs) in CO2 electroreduction reaction (CO2RR) has been overlooked. Herein, we prepared a series of Ni, N-codoped porous carbon (NiNC-T, T represents the temperature) catalysts by combining Ni phthalocyanine pyrolysis and acid etching strategy, which either contain only Ni SAs or both Ni SAs and Ni NPs. Notably, the NiNC-1100 catalyst with both Ni SAs and Ni NPs exhibited 99 % CO faradaic efficiency (FECO) at −0.66 V versus reversible hydrogen electrode (vs. RHE) and FECO above 98 % over a wide potential range (−0.66 V ∼ −1.06 V). Moreover, the FECO of NiNC-1100 remained above 95 % after 100 h of continuous electrocatalysis, which was significantly superior to that of the most advanced Ni single atom electrocatalysts. The systematic characterization results showed that the introduction of Ni NPs can promote the adsorption and activation of CO2 by increasing the electron cloud density of Ni SAs, thus enhancing the CO2RR catalytic performance.

Rapid Synthesis of Uniformly Small Nickel Nanoparticles for the Surface Functionalization of Epitaxial Graphene

AbstractNickel nanoparticles (Ni NPs) combined with carbon nanomaterials are of significant interest due to their wide range of applications, including catalysis, hydrogen storage, and sensor technologies. However, it is challenging to develop an efficient process to produce small and stable Ni NPs ideal for functionalizing graphene or substrates with complex geometries. For this purpose, a rapid, simple, and cost‐effective method is presented for synthesizing uniformly small Ni NPs. The process involves cooling aqueous solutions of Ni(OAc)2 and cetyltrimethylammonium bromide (CTAB) to ≈1 °C, followed by the rapid addition of NaBH4. Crucial parameters, such as temperature and stirring rate, are precisely controlled to ensure uniform particle growth, with the reaction completing in just a few minutes. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) characterizations reveal spherical NPs with an average diameter of ≈11 nm and a narrow size distribution. Additionally, epitaxial graphene (EG) samples are functionalized with the synthesized NPs and their arrangement on the surface and their stability upon thermal annealing are investigated. X‐ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) measurements demonstrate the degradation of CTAB, along with the recovery of Ni(0) under mild conditions (below 350 °C), with the NPs maintaining structural stability up to approximately 550 °C.

A detailed characterization study of Ni/CeO2 catalysts identifies Ni availability as the primary factor affecting CO2 methanation performance

The structure of a catalyst has a strong impact on its performance. Here we investigate the physicochemical properties of Ni/CeO2 in an attempt to draw structure–activity relationships for CO2 methanation. A combination of characterisation methods (X-ray diffraction (XRD), 4D Scanning Transmission Electron Microscopy (4D-STEM), CO chemisorption and oxygen storage capacity study etc.) clearly demonstrates the effect of Ni crystallite size, Ni availability (i.e. catalytically accessible Ni) and oxygen vacancies at the Ni-CeO2 interface in Ni/CeO2 during CO2 methanation. Among them, the role of exposed Ni active sites is highlighted, and two possible optimisation schemes i.e. changing the support calcination temperature and the final calcination atmosphere are proposed to obtain a better dispersal of Ni NPs (nanoparticles) on CeO2. Both modification methods do not affect the reaction route, and the activity differences of Ni/CeO2 can be explained by the various hydrogenation rate of formate species, as confirmed by in situ diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFTS) measurements.

Transition metal nickel nanoparticle-decorated g-C3N4 photocatalyst for improving tetracycline hydrochloride degradation

Metallic nickel nanoparticles (Ni0 NPs)-supported g-C3N4 have been developed using a solvothermal technique in N,N-dimethylformamide solvent. A uniformly dispersion of Ni0 NPs anchored on a g-C3N4 photocatalyst can improve the photocatalytic efficiency. The optimized Ni/g-C3N4 catalyst demonstrated a high photodegradation rate of TCH at 6.0 × 10−3 min−1 under LED light irradiation, which was approximately three times greater than that of the bare g-C3N4 catalyst. This superior performance originates from the capable separation of electron-hole pairs, facilitated by the strong interaction between Ni0 NPs and the host g-C3N4, as supported by optical and electrochemical property analysis. Our work provides a facile manner for the effective degradation of pollutants using heterojunction photocatalysts.

Acceptorless Dehydrogenation under Neat Reaction Conditions: Synthesis of 2-Aryl/Alkyl Quinazolinones Using Supported Ni NPs as Catalyst

AbstractWe report here a Ni-NPs-catalyzed one-pot synthesis of 2-alkyl/aryl quinazolinone motifs via acceptorless dehydrogenation of alcohol, condensation of an aldehyde intermediate with 2-aminobenzamide, followed by a second dehydrogenation of the cyclized intermediate. The protocol is atom-economical and require earth-abundant Ni as the catalyst. The present report involves the annulation of 2-aminobenzamide with various types of primary alcohols, including aryl/heteroaryl methanol, and aliphatic alcohols, and produces high yields of the desired products under neat conditions. The catalyst was synthesized via a 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 air at room temperature and displayed excellent activity in the acceptorless dehydrogenative coupling synthesis of quinazolinones and could be recycled five times without appreciable loss of its activity.

Preparation of PdNi bimetallic loaded amino modified porous carbon material catalyst based on chitosan and its applications

The utilization efficiency of palladium-based catalysts has sharply increased in many catalytic reactions. However, numerous studies have shown that preparing alloys of palladium with other metals has superior catalytic activity than pure palladium. Additionally, hierarchical porous carbon has gradually developed into an excellent carrier for loading bimetallic nanoparticles. In this study, we firstly pyrolyzed chitosan, sodium bicarbonate and nickel nitrate to create highly dispersed porous carbon materials doped with Ni NPs. The carbon materials were then grafted with silane coupling agent (APTMS) to afford them with amino groups on the surface. Taking advantage of the fact that Pd2+ can react with Ni in spontaneous reduction reaction, Pd was deposited on the surface of Ni to produce PdNi bimetallic-loaded carbon catalysts containing amino groups. The resulting catalysts were examined by a series of characterizations and were found to have a hierarchically porous structure and large specific surface area, which increased the number of active sites of the catalysts. In comparison to other Pd catalysts, the PdNi/HPCS-NH2 catalysts displayed remarkable activity for Suzuki coupling reaction and hydro reduction of nitroaromatics, which exhibited a high turnover frequency value (TOF) of 37,857 h−1 and 680.9 h−1, respectively. These were mainly due to the high dispersion of the PdNi NPs and the superior structure of the carriers. Moreover, the catalysts did not experience a significant decline in activity after ten cycles. All in all, this investigation has created a new approach for the fabrication of novel carriers for Pd catalysts, which is in line with the concept of green chemistry and recyclable.

Enhancing nitroaromatics reduction through synergistic participation of Ni NPs and nickel ferrite/C nanocomposite: A path towards greener industrial viability

Ni/Fe-citrate gel was reduced in an H2/Ar, forming Ni NPs decorated NiFe2O4-C for eco-friendly nitroaromatics reduction. In-depth characterization of the catalyst highlighted the synergistic interaction between Ni NPs and NiFe2O4 (Ni/NiFe2O4-C), achieving ∼ 99 % conversion of nitroaromatics into amines at 70 °C and 0.5 MPa H2 in water. The cooperative effects of Ni NPs, NiFe2O4, and carbon were instrumental in enhancing the adsorption of hydrogen and nitroaromatics, and the kinetic study showed effectively reducing the activation barrier for the reduction. The HR-TEM, XPS, and H2-TPR provided valuable insights into the formation of Ni NPs and the NiFe2O4 framework, emphasizing their synergistic relationship. Raman spectroscopy and TGA analysis confirmed the formation of carbon. Remarkably, the highly active Ni/NiFe2O4-C catalyst recycled for five cycles without losing activity. p-Aminophenol on 7 g will receive significant attention, emphasizing the substantial promise of this sustainable transition metal-based catalyst for the eco-friendly hydrogenation of nitroaromatics.

Mitochondrial Fission in Nickel Nanoparticle-Induced Reproductive Toxicity: An In Vitro GC-1 Cell Study.

Reproductive disorders and declining fertility rates are significant public health concerns affecting birth rates and future populations. Male infertility, often due to spermatogenesis defects, may be linked to environmental pollutants like nickel nanoparticles (Ni NPs). Ni NPs are extensively utilized across different industries. Nevertheless, their potential adverse effects cannot be overlooked. Previous studies have linked the reproductive toxicity induced by Ni NPs with disturbances in mitochondrial function. Mitochondrial division/fusion dynamics are crucial to their proper function, yet little is known about how Ni NPs perturb these dynamics and whether such perturbation contributes to the impairment of the male reproductive system. Herein, we demonstrated that the exposure of Ni NPs to the mouse-derived spermatogonia cell line (GC-1 cells) triggered DRP1-mediated mitochondrial division and the enhanced impairment of mitochondria, consequently promoting mitochondria-dependent cell apoptosis. Notably, both the mitochondrial division inhibitor (Mdivi-1) and lentiviral-transfected cells with low expression of Dnm1l-DK in these cells could mitigate the toxic effects induced by Ni NPs, pointing to the potential role of mitochondrial dynamics in Ni NP-induced reproductive toxicity. Collectively, our work contributes to the understanding of the mechanisms by which Ni NPs can impact male reproductive function and identifies mitochondrial division as a potential target for intervention.

Lattice-embedded Ni single-atom catalyst on porous Al2O3 nanosheets derived from Ni-doped carbon dots for efficient propane dehydrogenation

The controlled synthesis of highly durable single-atom catalysts (SACs) for high-temperature applications remains a great challenge. Herein, we develop a facile strategy to construct Al2O3 lattice-embedded Ni SAC via thermal treatment of aluminum oxide encapsulated Ni-doped carbon dots (Ni-CDs@Al2O3). Detailed studies reveal that the Ni atoms are released from carbon matrix and simultaneously captured by cation defects formed in situ within a phase transformation of aluminum oxide. Al2O3 stabilized Ni atoms via Ni-O4 coordination are well illustrated by combined characterizations. For propane dehydrogenation, reactivity measurements show that the center of Ni-O ion pairs effectively activates C3H8 and the higher rate of C3H6 formation on Ni SAs than Ni NPs, by a factor of 12, is the result of inhibition of C-C bond cleavage involving side reactions, as identified by density functional calculations. Beyond that, this lattice-embedded Ni SAC exhibits superior stability and recyclability in long-term operation with little coke accumulation.

Electrochemiluminescence Enhancement and Passivation Mitigation in Carbon Nitride Semiconductors via an Integrated Ternary Heterostructure Strategy.

In recent years, carbon nitride (CN) has attracted substantial attention in the field of electrochemiluminescence (ECL) applications, owing to its outstanding optical and electronic properties. However, the passivation of CN during the ECL process has contributed to reduced stability and poor repeatability. While some studies have tried to boost ECL performance by altering CN through doping and vacancies, effectively suppressing CN passivation at high potentials continues to be challenge. In this study, the built-in electric field and the Schottky barrier effect is used to expedite the transfer of electrons from CN to the molybdenum disulfide (MoS2) conduction band. This transfer deterred excessive electron injection into the CN band, thus mitigating its electrochemical degradation. Moreover, by introducing nickel nanoparticles (Ni NPs) as catalytic active sites, it is facilitated that the decomposition of potassium persulfate (K2S2O8), thereby enhancing both the stability and intensity of ECL emission. In the end, the application of ternary heterostructure as sensing platform for the cancer biomarker carcinoembryonic antigen (CEA) demonstrated high sensitivity. This research introduces a novel approach to overcome CN passivation, paving the way for more promising applications of CN in energy, environmental, and biosensing fields.

Anhydrous metal nanoparticle suspensions using deep eutectic solvents (DES) – Green approach to metal nanoparticles production

Following the principles of green chemistry and the concept of sustainable development, a method was developed to obtain suspensions of metal nanoparticles, i.e. Ag, Au, Cu, Ni and Sn in deep eutectic solvents (DESs). The choice of DES (type III quaternary ammonium salt + hydrogen bond donor) as the base for the preparation of metal nanoparticles allowed the elimination of unnecessary solvents and the removal of the introduction of additional reactants, as DES acted as both a metal ion reducer and a stabiliser of the formed nanoparticles in the system. Running the process to obtain metal nanoparticle suspensions in an anhydrous environment (possible trace water content) ensured high stability of the nanoparticles. Suspensions with a nanoparticle concentration of 250 mg/kg were characterised by a reduced pH of 5–6, which in the future increases their application potential in, among others, coatings exposed to skin or in acidic concentrates used for cleaning. Spherical nanoparticles with an average size of approx. 14.40, 14.00, 60.38, 26.50 and 16.36 nm were obtained for Ag, Au, Cu, Ni and Sn NPs, respectively. The developed method will enable the future use of metal nanoparticle suspensions in DESs as additives both in materials sensitive to the aqueous environment and in products with neutral or acidic pH. The developed method is also a versatile approach to the synthesis of nanoparticles, following the principles of green chemistry by maximising the potential of the reactants used.

Tunable Syngas Formation at Industrially Relevant Current Densities via CO2 Electroreduction and Hydrogen Evolution over Ni and Fe-derived Catalysts obtained via One-Step Pyrolysis of Polybenzoxazine Based Composites.

Simultaneous electroreduction of CO2 and H2O to syngas can provide a sustainable feed for established processes used to synthesize carbon-based chemicals. The synthesis of MOx/M-N-Cs (M = Ni, Fe) electrocatalysts reported via one-step pyrolysis that shows increased performance during syngas electrosynthesis at high current densities with adaptable H2/CO ratios, e.g., for the Fischer-Tropsch process. When embedded in gas diffusion electrodes (GDEs) with optimized hydrophobicity, the NiOx/Ni-N-C catalyst produces syngas (H2/CO = 0.67) at -200mA cm-2 while for the FeOx/Fe-N-C syngas production occurs at ≈-150mA cm-2. By tuning the electrocatalyst's microenvironment, stable operation for >3h at -200mA cm-2 is achieved with the NiOx/Ni-N-C GDE. Post-electrolysis characterization revealed that the restructuring of the catalyst via reduction of NiOx to metallic Ni NPs still enables stable operation of the electrode at -200mA cm-2, when embedded in an optimized microenvironment. The ionomer and additives used in the catalyst layer are important for the observed stable operation. Operando Raman measurements confirm the presence of NiOx during CO formation and indicate weak adsorption of CO on the catalyst surface.

Size effect of nickel from nanoparticles to clusters to single atoms for electrochemical CO2 reduction

The size effect of Ni–N–C catalysts from nanoparticles to clusters to single atoms on electrochemical CO2 reduction is investigated. The Ni single atoms are active for CO formation, while Ni NPs and Ni clusters enable syngas production.

A comparative study of α-Ni(OH)2 and Ni nanoparticle supported ZIF-8@reduced graphene oxide-derived nitrogen doped carbon for electrocatalytic ethanol oxidation.

Ethanol electrooxidation is an important reaction for fuel cells, however, the major obstacle to ethanol electrocatalysis is the splitting of the carbon-carbon bond to CO2 at lower overpotentials. Herein, a ZIF-8@graphene oxide-derived highly porous nitrogen-doped carbonaceous platform containing zinc oxide was attained for supporting a non-precious Ni-based catalyst. The support was doped with the disordered α-phase Ni(OH)2 NPs and Ni NPs that are converted to Ni(OH)2 through potential cycling in alkaline media. The Ni-based catalysts exhibit high electroactivity owing to the formation of the NiOOH species which has more unpaired d electrons that can bond with the adsorbed species. From CV curves, the EOR onset potential of the α-Ni(OH)2/ZNC@rGO electrode is strongly shifted to negative potential (Eonset = 0.34 V) with a high current density of 8.3 mA cm-2 relative to Ni/ZNC@rGO. The high catalytic activity is related to the large interlayer spacing of α-Ni(OH)2 which facilitates the ion-solvent intercalation. Besides, the porous structure of the NC and the high conductivity of rGO facilitate the kinetic transport of the reactants and electrons. Finally, the catalyst displays a high stability of 92% after 900 cycles relative to the Ni/ZNC@rGO and commercial Pt/C catalysts. Hence, the fabricated α-Ni(OH)2/ZNC@rGO catalyst could be regarded as a potential catalyst for direct EOR in fuel cells.

3D graphene decorated with nickel nanoparticles: in situ synthesis, enhanced dispersibility, and absorption-dominated electromagnetic interference shielding

Utilizing the complexation of carboxyl groups with Ni(ii), 3D graphene with highly dispersed Ni NPs was achieved via laser fabrication.

Electrodeposition of Reactive Aluminum-Nickel Coatings in an AlCl3:[Emim]Cl Ionic Liquid Containing Nickel Nanoparticles

The electrodeposition of reactive aluminum-nickel dispersion coatings was performed by pulsed direct current (PDC) onto copper substrates in the ionic liquid 1.5:1 AlCl3:[EMIm]Cl (1-Ethyl-3-methylimidazolium chloride). A cathodic current density of 15 mA/cm2 was used with two different frequency (f)/duty cycle (r c) combinations, i.e., f= 0.33 Hz/ r c= 0.33 (t on= 1 s, t off= 2 s) and f= 0.05 Hz/ r c= 0.5 (t on= 10 s, t off= 10 s). Several electrochemical techniques like Cyclic Voltammetry, Electrochemical Impedance Spectroscopy and Open Circuit Potential measurements were used besides X-Ray Diffraction, Confocal Microscopy, Scanning Electron Microscopy, Atomic Absorption Spectroscopy and 27Al/1H Nuclear Magnetic Resonance in order to shed more light on the mechanism of Ni particle incorporation into the Al metal matrix. We could show that particle incorporation at the beginning of the deposition mainly takes place via particle adsorption at the substrate. As the thickness of the coating increases, it seems that the main mechanism for particle incorporation is via the reduction of Al2Cl7 - ions adsorbed at the particles surface. Three different Ni NPs concentration were tested in this work: 5, 10 and 20 g/L. Although a considerable high incorporation of Ni NPs has been achieved from the IL electrolyte containing the highest concentration of Ni NPs (i.e. ~ 33 wt.% from a 20 g/L of Ni NPs bath), a high concentration of NPs in the ionic liquid resulted having a negative effect in terms of quality of the coatings, due to local cathodic passivation, or solidification of the electrolyte in a poorly conductive compound. This phenomenon has been related to the increase in viscosity originating from the decrease in rotational mobility of the [EMIm]+ cation, as detected by 1H NMR. Despite this fact, almost equivalent amounts of Ni and Al (Ni ~ 45 wt.% and Al ~ 44 wt.%) have been detected by energy-dispersive X-ray spectroscopy mapping in some areas of the coatings prepared with longer pulse off-time (f = 0.05 Hz, t off= 10 s). Such a layer composition would be convenient for the targeted application. Nevertheless, more studies related to the homogeneity of the deposits, as well as ignition tests, must be performed to evaluate the suitability of the coatings to trigger a self-propagating reaction.

Facile Fabrication of Nickel Supported on Reduced Graphene Oxide Composite for Oxygen Reduction Reaction.

Due to the depletion of fossil fuels, the demand for renewable energy has increased, thus stimulating the development of novel materials for energy conversion devices such as fuel cells. In this work, nickel nanoparticles loaded on reduced graphene oxide (Ni/rGO) with small size and good dispersibility were successfully prepared by controlling the pyrolysis temperature of the precursor at 450 °C, assisted by a microwave-assisted hydrothermal method, and exhibited enhanced electrocatalytic activity towards oxygen reduction reaction (ORR). Additionally, the electron enrichment on Ni NPs was due to charge transfer from the rGO support to metal nickel, as evidenced by both experimental and theoretical studies. Metal-support interactions between nickel and the rGO support also facilitated charge transfer, contributing to the enhanced ORR performance of the composite material. DFT calculations revealed that the first step (from O2 to HOO*) was the rate-determining step with an RDS energy barrier lower than that of the Pt(111), indicating favorable ORR kinetics. The HOO* intermediates can be transferred onto rGO by the solid-phase spillover effect, which reduces the chemical adsorption on the nickel surface, thereby allowing continuous regeneration of active nickel sites. The HO2- intermediates generated on the surface of rGO by 2e- reduction can also efficiently diffuse towards the nearby Ni surface or the interface of Ni/rGO, where they can be further rapidly reduced to OH-. This mechanism acts as the pseudo-four-electron path on the RRDE. Furthermore, Ni/rGO-450 demonstrated superior stability, methanol tolerance, and durability compared to a 20 wt% Pt/C catalyst, making it a cost-effective alternative to conventional noble metal ORR catalysts for fuel cells or metal-air batteries.

Amine-Functionalized SBA-15 Mesoporous Silica-Anchored Ni Nanocatalyst for CO2 Hydrogenation Reaction

Abstract: In this study, we successfully synthesized amine-functionalized SBA-15 mesoporous silicasupported Nickel nanoparticles (Ni NPs) and investigated their potential for CO2 transition to formic acid via high-pressure hydrogenation reaction. The metal-support interface between the Ni NPs and the amine-functionalized SBA-15 mesoporous silica was examined using various techniques, including BET, TEM, and XPS analyses. Our findings reveal a robust metal-support interaction between the NiNPs and the mesoporous silica substrate, highlighting the suitability of the catalyst for the CO2 conversion reaction. Additionally, the catalyst CAT$Ni-1 exhibited good catalytic activity over CAT$Ni-2 and CAT$Ni-3, and we were able to recycle them up to five runs with no significant reduction in catalytic activity. These results suggest that the synthesized Ni NP catalysts have the potential for large-scale CO2 conversion, contributing to the development of sustainable technologies for reducing greenhouse gas emissions.

Ultralow Pd bimetallic catalysts boost (de)hydrogenation for reversible H2 storage

The facile catalytic reversible (de)hydrogenation of liquid organic hydrogen carriers (LOHC) using a single catalyst holds great value for onboard hydrogen storage. Herein, we develop a bimetallic catalyst Pd1Ni based on nonnoble metal Ni with ultralow Pd of 0.05 wt%, which enables reversible (de)hydrogenation of NPC and supports multiple cycles of reversible hydrogen uptake and release. Notably, the bimetallic catalyst Pd1Ni exhibits more excellent catalytic performance on the dehydrogenation reaction of dodecahydro-N-propylcarbazole (12H-NPC) than the 1%Pd catalyst and similar catalytic performance on the hydrogenation reaction of NPC compared to the 1%Ru catalyst. The astonishing catalytic efficiency of Pd1Ni catalysts is due to the ideal electronic structure between ultralow Pd and Ni NPs allowing rapid interfacial electron transfer to intermediates, as revealed by structural analyses and density functional theory (DFT) computations.