NiO Ni Nanoparticles Research Articles

Highly dispersed Ni nanoparticles confined in mesoporous SBA-15 for methane dry reforming with improved coke resistance and stability

Methane dry reforming (DRM) is a promising route for sustainable syngas production, in which Ni-based catalysts face challenges of metal sintering and coke formation. In this work, highly dispersed Ni nanoparticles (NPs) embedded in the mesopores of SBA-15 were prepared using a simple solid-state impregnation (SSI) method. TEM and cross-section HRTEM results clearly indicated that ultra-small Ni NPs (3–4 nm) were orderly dispersed within the mesopores of the SBA-15 support. Compared with the conventional wetness impregnation (WI) method, the Ni/SBA-15 catalyst prepared by solid-state impregnation method possessed much better catalytic activity, stability, and coke resistance in DRM. In-situ DRIFTS and semi-in-situ XRD were used to elucidate the dispersion and encapsulation mechanism of Ni within the mesopores of SBA-15 during the sample preparation process. Specifically, WI formed large NiO particles, while SSI formed smaller NiO NPs with stronger interaction between metal and support (SIMS) via forming Ni-O-Si species which is beneficial for the DRM reactivity. This work establishes relationships among catalyst preparation, structure, and DRM performance, paving the way for general template-assisted methods to prepare nanometallic catalysts for various applications.

Utilizing biosynthesized nickel(II) oxide nanoparticles in the synthesis of bis(indolyl)arylmethanes with anti-lung cancer properties

The recently prepared nanophotocatalyst Ni-NiO is introduced as an effective mediator in the one-pot two-component synthesis of various substituted bis(indolyl)arylmethanes and as potent anti-lung cancer agent. The inception of this environmental friendly photocatalyst stems from the biosynthesis process utilizing Glycyrrhiza Glabra (licorice) leaves extract that is an active plant with potential applications in lung cancer treatment. Familiar characterization techniques including XPS, UV–Vis, XRD, FT-IR, FE-SEM, TEM, and EDS provided a comprehensive information on the physicochemical properties of Ni-NiO nanoparticles. Subsequently, the Ni-NiO nanophotocatalyst was harnessed for the synthesis of bis(indolyl)arylmethanes under visible light. The utilized photocatalyst underscored reasonable stability, reusability, and practical utility. Moreover, cytotoxicity evaluations employing the MTT experiment on A549 lung cancer cell line proved promising potential of Ni-NiO nanoparticles and bis(indolyl)phenylmethane in inhibiting cancer cell proliferation. Findings revealed that both biosynthesized Ni-NiO nanoparticles and the tested bis(indolyl)phenylmethane have sufficient therapeutic potential against the performed cancer cell line. This innovative approach represents a significant contribution to the field of cancer research and underscores the potential for developing next-generation cancer treatments.

Multiscale Confinement Engineering for Boosting Overall Water Splitting by One-Step Stringing of a Single Atom and a Janus Nanoparticle within a Carbon Nanotube.

Enzyme-mimicking confined catalysis has attracted great interest in heterogeneous catalytic systems that can regulate the geometric or electronic structure of the active site and improve its performance. Herein, a liquid-assisted chemical vapor deposition (LCVD) strategy is proposed to simultaneously confine the single-atom Ru sites onto sidewalls and Janus Ni/NiO nanoparticles (NPs) at the apical nanocavities to thoroughly energize the N-doped carbon nanotube arrays (denoted as Ni/NiO@Ru-NC). The bifunctional Ni/NiO@Ru-NC electrocatalyst exhibits overpotentials of 88 and 261 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at 100 mA cm-2 in alkaline solution, respectively, all ranking the top tier among the carbon-supported metal-based electrocatalysts. Moreover, once integrated into an anion-exchange membrane water electrolysis (AEMWE) system, Ni/NiO@Ru-NC can act as an efficient and robust bifunctional electrocatalyst to operate stably for 50 h under 500 mA cm-2. Theoretical calculations and experimental exploration demonstrate that the confinement of Ru single atoms and Janus Ni/NiO NPs can regulate the electron distribution with strong orbital couplings to activate the NC nanotube from sidewall to top, thus boosting overall water splitting.

The Enhancing Effect of α–FeOOH on Ni Surfaces Toward Electrolytic Water Splitting

For decades Ni has been known as an electrocatalyst for the oxygen evolution reaction (OER); however, the crucial role that Fe plays in enhancing the electrocatalytic activity of Ni still requires deeper investigation and understanding. Herein, some light on the role of Fe by studying the structural evolution of different Ni‐based electrocatalysts upon the electrolytic addition of different quantities of Fe are shaded. Colloidal Ni and NiO, as well as Ni, NiO, and NiNiO nanoparticles, are synthesized and electrochemically characterized in Fe‐free and Fe‐doped KOH electrolytes. Voltammetry and in situ Raman spectroscopy show that higher concentrations of Fe in the electrolyte lead to lower OER overpotentials due to the presence of α–FeOOH.

Preparation and performance of a graphene-(Ni-NiO)-C hybrid as the anode of a lithium-ion battery

AbstractA graphene-(Ni-NiO)-C hybrid was prepared by dissolving nickel acetate and glucose in water to form a solution that was mixed with a graphene oxide (GO) aqueous suspension, hydrothermally treated at 180 °C for 24 h, carbonized at 700 °C for 3 h in Ar and calcined at 300 °C for 3 h in air. Results indicated that Ni(OH)2 formed during the hydrothermal treatment was converted to metallic Ni during carbonization, which was partly oxidized to NiO during calcination. When used as the anode material of a lithium-ion battery, it had a high initial capacity of 711.6 mA h g−1, which increased to 772.1 mA h g−1 after 300 cycles. For comparison, the sample without added GO had a much lower initial capacity of 584.7 mA h g−1, which decreased to 148.8 mA h g−1 after 300 cycles. Hybridization of the Ni-NiO nanoparticles with carbon inhibited their aggregation. The GO addition led to the formation of a conducting network, which alleviated the large volume expansion during lithiation, prevented the electrode from cracking during cycling and increased the surface area for easy access of the electrolyte. These factors jointly contributed to the obvious improvement in the electrochemical performance of the graphene-(Ni-NiO)-C anode.

Efficient Oxygen Evolution Reaction Catalyzed by Ni/NiO Nanoparticles Produced by Pulsed Laser Ablation in Liquid Environment

Electrochemical water‐splitting, sustained by renewable energy, is aimed at green H2 production. Efficient and sustainable electrocatalysts are required for a proper energy transition. Oxygen evolution reaction (OER) in alkaline electrolyte can be pursued by using earth‐abundant elements‐based catalysts, such as Ni oxyhydroxides. A proper optimization of intrinsic properties and synthesis procedure is still needed. Herein, the synthesis of Ni/NiO nanoparticles (NPs) through a physical and green technique, pulsed laser ablation in liquid (PLAL), is presented. Ablating a Ni target in deionized water, at different ablation times, leads to NP dispersions used for realization of OER electrode onto graphene paper. Ion‐beam analysis of catalysts amount and homogeneity of NP‐based electrode is performed for the electrode optimization in terms of electrochemical performances. An overpotential at 10 mA cm−2 of 306 mV is achieved for 40 μg cm−2 of catalyst, while lowering the catalyst amount to 8 μg cm−2, unprecedented turnover frequency of 0.20 s−1 and mass activity of ≈1.3 A mg−1 are reached. These data show that Ni/NiO NPs produced by PLAL are highly effective for OER in alkaline media and encourage the use of PLAL as a green and efficient technique for electrocatalyst production.

Effect of Alkyl Chain Length of Amines on the Micro-structural and Magnetic Properties of Stabilized Ni-NiO Nanoparticles

Effect of Alkyl Chain Length of Amines on the Micro-structural and Magnetic Properties of Stabilized Ni-NiO Nanoparticles

MOFs-derived integrated flower shaped porous carbon anchored with core-shell Ni-NiO nanoparticles as efficient multifunctional electrode for Li–S batteries

Designing electrodes with structures suitable for storing and fixing sulfur to overcome the inherent shortcomings of lithium-sulfur (Li–S) batteries is an effective approach to achieving commercial application. Indeed, multifunctional electrodes constructed with sulfur immobilization substrate and efficient catalyst has dramatically improved the utilization of sulfur. However, structurally designing the substrate and achieving uniform dispersion of catalytic remain huge challenges. In this paper, a metal-organic frameworks derived flower shaped nitrogen doped carbon (NC) materials anchored with core-shell Ni-NiO nanoparticles loaded on carbon paper (CP) was fabricated, which equipped with 3D conductive network and hierarchical porous structure physically restrict polysulfide shuttling. Furthermore, well-proportioned Ni-NiO nanoparticles were induced into host to bond with polysulfides further catalyzed the electrochemical reaction. Notably, the S@Ni-NiO@NC/CP exhibited high specific capacity with 1332.9 mAh/g initial specific capacity at 0.5 C and maintained at 896.3 mAh/g after 200 cycles. And S@Ni-NiO@NC/CP can achieves an initial capacity of 1095.7 mA h g−1 even with high sulfur loading of 4.6 mg/cm2. Electrochemical test results indicated that the introduction of Ni-NiO catalyst can improve the kinetics and reduce the reaction overpotential (ηE), and further affects the value of concentration overpotential (ηC) ultimately leads to the increase of battery capacity.

Phase structure tuning of graphene supported Ni-NiO Nanoparticles for enhanced urea oxidation performance

The sluggish kinetics of urea electro-oxidation seriously limits its application in hydrogen production and wastewater treatment. Herein, we demonstrated an easy freeze-drying/annealing approach induced phase structure tuning of graphene supported Ni-NiO nanoparticles system for efficiently boosting urea oxidation performance. The annealing temperature was found significant to influence the Ni precursors decomposition, crystal structure formation and catalytic performance for urea oxidation. By increasing the temperature from 350 °C to 550 °C, more metallic Ni was formed in the Ni-NiO system, and because of the efficient Ni-NiO synergistic effect and conductivity improvement, the sample obtained at 450 °C exhibited the highest catalytic activity and stability for urea oxidation. Specifically, the current density at 0.5 V was 38.24 mA cm−2, about 5.6 and 30 times of the control sample of graphene supported NiO and Ni respectively. Efficient kinetics and rapid charge transfer-ability were also found for urea oxidation by a series of electro-kinetics analysis. The current work showed an easy way for Ni-based catalyst structure tuning with enhanced kinetics for urea oxidation, which is helpful for the sustainable utilization of urea molecular in electrochemical energy.

Atomic-scale imaging of the growth and transformation of Pt3Ni–NiO nanoparticles

The evolution of Pi3Ni–NiO nanoparticles was visualized in a liquid cell.

Non-precious and accessible nanocomposite of iron oxide on PDDA-Modified graphene for catalyzing oxygen reduction reaction

Abstract Nanocomposite catalysts composed of non-precious nanoparticles anchored by modified graphene for oxygen reduction reactions (ORRs) are the emphasis of research nowadays for wide application in electrocatalyst systems. Herein, an endeavor is made to report on a one-pot synthesis method to produce a catalyst for Fe3O4 and Ni–NiO nanoparticles on Polydiallyldimethylammonium chloride-modified graphenes (PDDA-G). The nanocomposite is characterized by spectral measurements, using scanning electron spectroscopy (SEM), transmitting electron spectroscopy (TEM), x-ray diffractometer (XRD) and Raman spectroscopy to reveal its microstructure. Through a layer-by-layer PDDA-G investigation, a significant anchoring of nanoparticles and maintenance of the graphene with good electron transporting properties and spatial distance in nanoscale by PDDA is achieved. Additionally, the electrochemical properties of Fe3O4@PDDA-G and Ni–NiO@PDDA-G are demonstrated by linear scan voltammetry (LSV) with rotation disk electrode (RDE). Fe3O4@PDDA-G displays prominent ORR activity in 2-electron and 4-electron pathways, and better ORR mass activities than Ni–NiO@PDDA-G and commercial Pt/C. The results of this study provide a new strategy to develop material design approaches for high-performance electrocatalysts to be employed in fuel cells.

In-situ electrolytic synthesis and superior lithium storage capability of Ni–NiO/C nanocomposite by sacrificial nickel anode in molten carbonates

Abstract Herein, we demonstrate a facile electrolytic strategy to synthesize a kind of Ni–NiO/C nanocomposite via electroreduction of molten Li–Na–K carbonates synchronously combined with sacrificial nickel anode. Benefiting from its unique in situ synthesis mechanism, the Ni–NiO/C nanocomposite exhibits well-interconnected architecture with fine Ni–NiO nanoparticles embedded into electrolytic carbon matrix. The as-fabricated electrode shows ultra-long cycle stability (achieving a high capacity of 455 mA h g−1 at 1 A g−1 after 1500 cycles, average coulombic efficiency 99.88%) and impressively improved rate capability, comparing with the reported Ni–NiO/C nanocomposites. Such a superior lithium storage properties originates from the in situ formed nanoarchitecture of Ni–NiO/C. This research offers a distinctive pathway for constructing novel composite materials for advanced lithium storage.

Influence of Synthesis Conditions on the Structure of Nickel Nanoparticles and their Reactivity in Selective Asymmetric Hydrogenation

AbstractUnsupported and SiO2‐supported Ni nanoparticles (NPs) were synthesised via hot‐injection colloidal route using oleylamine (OAm) and trioctylphosphine (TOP) as reducing and protective agents, respectively. By adopting a multi‐length scale structural characterization, it was found that by changing equivalents of OAm and TOP not only the size of the nanoparticles is affected but also the Ni electronic structure. The synthetized NPs were modified with (R,R)‐tartaric acid (TA) and investigated in the asymmetric hydrogenation of methyl acetoacetate to chiral methyl‐3‐hydroxy butyrate. The comparative analysis of structure and catalytic performance for the synthetized catalysts has enabled us to identify a Ni metallic active surface, whereby the activity increases with the size of the metallic domains. Conversely, at the high conversion obtained for the unsupported NPs there was no impact of particle size on the selectivity. (R)‐selectivity was very high only on catalysts containing positively charged Ni species such as over the SiO2‐supported NiO NPs. This work shows that the chiral modification of metallic Ni NPs with TA is insufficient to maintain high selectivity towards the (R)‐enantiomer at long reaction times and provides guidance for the engineering of long‐term stable enantioselective catalysts.

Ni/NiO nanoparticles embedded inporous graphite nanofibers towards enhanced electrocatalytic performance

Ni/NiO nanoparticles (NPs) were encapsulated in one dimensional (1D) graphitic nanofibers using a two-step calcination route. The precursor fibers obtained by electrospinning were heated in air at a low temperature firstly, followed by calcination at high temperature in Ar. With changing the amount of Ni precursors and preparation conditions, the morphology of resulting samples were adjusted from porous nanofiber to nanotube-loaded bulky material. The sizes and distribution of Ni/NiO NPs also changed. These NPs were in and on the nanofibers or located on the top of nanotubes. Electrochemistry test results indicate that resulting sample revealed enhanced electrocatalytic hydrogen evolution reaction (HER) when the precursor contained 0.5 mmol Ni. In an alkaline medium, the current density of samples could reach up to 280 mA cm−2. This is ascribed to the homogeneous distribution of Ni/NiO NPs and the porous structure of nanofibers with a large surface area of 251 m2/g. In contrast, the HER performance of nanotube-loaded bulky material get worse due to the disadvantage of specific surface area.

Highly-Dispersed Ni-NiO Nanoparticles Anchored on an SiO2 Support for an Enhanced CO Methanation Performance

Highly-dispersed Ni-NiO nanoparticles was successfully anchored on an SiO2 support via a one-pot synthesis and used as heterogeneous catalysts for CO methanation. The as-obtained Ni-NiO/SiO2 catalyst possessed a high Ni content of 87.8 wt.% and exhibited a large specific surface area of 71 m2g−1 with a main pore diameter of 16.7 nm. Compared with an H2-reduced Ni-NiO/SiO2 (i.e., Ni/SiO2) catalyst, the Ni-NiO/SiO2 displayed a superior CO methanation performance. At the temperature of 350 °C, the Ni-NiO/SiO2 showed a CO conversion of 97.1% and CH4 selectivity of 81.9%, which are much better values than those of Ni/SiO2. After a 50-h stability test, the Ni-NiO/SiO2 catalyst still had an overwhelming stability retention of 97.2%, which was superior to the 72.8% value of the Ni/SiO2 catalyst.

Deposition of Ni–NiO nanoparticles on the reduced graphene oxide filled polypyrrole: evaluation as cathode catalyst in microbial fuel cells

Herein, we fabricated thein situpolymerization of pyrrole (Py) on reduced graphene oxide (rGO), formulated as a nanocomposite support matrix for the deposition of nickel–nickel oxide (Ni–NiO) nanoparticles (NPs), as a cost-effective cathode catalyst for application in microbial fuel cells.

Effects of a light coloured cotton rug use on horse thermoregulation and behavior indicators of stress

Ni–graphite core–shell nanoparticles (CSNPs), which consisted of Ni nanoparticles (NPs) wrapped with several graphene layers, were grown by the thermal reduction of NiO NPs using H2. The effect of the synthesis temperature (800, 900, 1000, and 1100 °C) on the formation of multilayer graphene shells on the Ni core NPs was investigated to evaluate the structural and electrical characteristics of the particles. The proposed chemical reactions for the formation of Ni NPs can be summarized as follows: formation of liquid Ni by the reduction of NiO, thermal decomposition of the NiO phase, and formation of multilayer graphene shell because of the supersaturation of C in the liquid Ni phase. The resistivity of the electrode pattern fabricated with the Ni–graphite CSNP paste was found to be 6.75 × 10−3 Ω cm. Further, the power conversion efficiency of bulk heterojunction solar cells fabricated with the Ni–graphite CSNPs is higher than that of cells fabricated without the Ni−graphite CSNPs. Thus, our Ni–graphite CSNPs can be employed as a highly efficient electrode material in bulk heterojunction solar cells.

Conductive electrodes based on Ni–graphite core–shell nanoparticles for heterojunction solar cells

Abstract Ni–graphite core–shell nanoparticles (CSNPs), which consisted of Ni nanoparticles (NPs) wrapped with several graphene layers, were grown by the thermal reduction of NiO NPs using H2. The effect of the synthesis temperature (800, 900, 1000, and 1100 °C) on the formation of multilayer graphene shells on the Ni core NPs was investigated to evaluate the structural and electrical characteristics of the particles. The proposed chemical reactions for the formation of Ni NPs can be summarized as follows: formation of liquid Ni by the reduction of NiO, thermal decomposition of the NiO phase, and formation of multilayer graphene shell because of the supersaturation of C in the liquid Ni phase. The resistivity of the electrode pattern fabricated with the Ni–graphite CSNP paste was found to be 6.75 × 10−3 Ω cm. Further, the power conversion efficiency of bulk heterojunction solar cells fabricated with the Ni–graphite CSNPs is higher than that of cells fabricated without the Ni−graphite CSNPs. Thus, our Ni–graphite CSNPs can be employed as a highly efficient electrode material in bulk heterojunction solar cells.

An ultralight nitrogen-doped carbon aerogel anchored by Ni-NiO nanoparticles for enhanced microwave adsorption performance

Low density electromagnetic microwave adsorption materials (MAMs) have attracted much attention. Here, chitosan was used to prepare ultralight nitrogen-doped carbon aerogel anchored by Ni-NiO nanoparticles (Ni-NiO/NCA) via an explosion method. The results showed that NCA had better dielectric properties and lower density (0.46 g/cm3). The Ni-NiO/NCA effectively combines multiple dielectric/magnetic loss mechanisms. When the absorbing layer is 1.5 mm, the sample has magnetic properties. The strongest absorption is at −41.9 dB with a frequency of 15.2 GHz; the density is only 0.42 g/cm3. We believe this nitrogen-doped carbon aerogel anchored by magnetic nanoparticles via an explosion method can quickly prepare lightweight electromagnetic MAMs.

Hierarchical Porous Prism Arrays Composed of Hybrid Ni-NiO-Carbon as Highly Efficient Electrocatalysts for Overall Water Splitting.

Searching for an economical and efficient water splitting electrocatalyst is still a huge challenge for hydrogen production. This work reports one-step synthesis of hierarchical porous prism arrays (HPPAs) composed of Ni-NiO nanoparticles embedding uniformly in graphite carbon (Ni-NiO/C HPPAs), which is derived from metal-organic framework (CPO-27-Ni) prism arrays grown on nickel foam (NF). Remarkable features of the prism arrays, synergistic effect of Ni-NiO/C, porous graphite carbon, high conductive NF, and good contact between catalyst and current collector result in excellent electrocatalytic performance of Ni-NiO/C HPPAs@NF. Ni-NiO/C HPPAs@NF shows a small overpotential of ∼49.48 mV at the current density of 10 mA cm-2, low Tafel slope of 74 mV dec-1 and robust stability for hydrogen evolution reaction (HER) in alkaline media. Especially, the overpotential for HER of Ni-NiO/C HPPAs@NF is only ∼132 mV at the current density of 185 mA cm-2, almost the same as the value from the Pt/C. Furthermore, for oxygen evolution reaction in basic media, Ni-NiO/C HPPAs@NF shows better catalytic activity, lower Tafel slope and higher durability than precious IrO2. The above finding offers an effective strategy to design the bifunctional electrocatalysts for overall water splitting.