Supported Nickel Oxide Research Articles

Expanded Two-Dimensional Layered Vermiculite Supported Nickel Oxide Nanoparticles Provides High Activity for Acetylene Carbonylation to Synthesize Acrylic Acid

When acrylic acid (AA) is synthesized from acetylene carbonylation using supported nickel as a heterogeneous catalyst, it is important to select a suitable carrier material. Accordingly, we prepared a series of nickel-loaded catalysts using treated expanded two-dimensional layered vermiculite (2D-VT), NaY, HY, MCM-41, and talcum powder (TP) as carriers. As a result, it was found that the calcined nickel-supported expanded NiO/2D-VT exhibited excellent catalytic performance as a catalyst. The highest yield (83.1%) was obtained. We used XRD, SEM, TEM, BET, FTIR, TGA, ICP and XPS to thoroughly characterize the catalysts. It was found that the two-dimensional layered structure of vermiculite (VT) itself with a hydroxyl structure provides a loading site for the active metal NiO, which promotes the formation of a hydrogen carboxyl group. And the excellent thermal stability of VT inhibits the formation of carbon deposits in the NiO/2D-VT catalyst during the reaction. Compared with other catalysts, the NiO/2D-VT catalyst has significantly less carbon deposits, more cycles are used, and activity decreases more slowly. In addition, we also studied the reasons for the decrease in the activity of the NiO/2D-VT catalyst used repeatedly, and found that the loss of NiO supported on the VT two-dimensional layered structure is the main reason for the catalyst deactivation.

Spinel oxides as coke-resistant supports for NiO-based oxygen carriers in chemical looping combustion of methane

Due to their high activity for methane conversion under a cyclic redox scheme, supported nickel oxides are among the most extensively investigated oxygen carrier materials for chemical looping combustion (CLC) and reforming (CLR) of methane. However, coke formation remains as a key challenge for Ni-containing oxygen carriers. The current study investigates the effect of reducible, spinel-structured supports to enhance coke resistance of NiO-based oxygen carriers. It was hypothesized that reducible supports capable of continued yet slow lattice oxygen donation in the presence of methane can actively retard coke formation on the surface of the oxygen carriers. To evaluate such effects, NiFe2O4, MgFe2O4, and BaFe2O4 are investigated as coke-resistant, reducible supports for NiO using mass spectrometry (MS) and thermogravimetric analysis (TGA) during chemical looping cycles. All three reducible supports were capable of continuous oxygen donation over an extended period of time (>40 min) without signs of coke formation. When used as supports for NiO, the resulting oxygen carriers showed no sign of carbon deposition under typical methane CLC environments. In comparison, NiO supported on inert MgAl2O4 exhibited significant coke formation after only 2.5 min. Moreover, NiO supported on NiFe2O4 and BaFe2O4 exhibited faster redox activity and higher oxygen carrying capacity when compared to the inert MgAl2O4-supported NiO. Detailed investigation of the reduction behavior of NiFe2O4-supported NiO revealed extensive solid-state reactions and Ni/Fe exchanges among the support, NiO, and newly formed phases. Specifically, initial weight loss in NiFe2O4-supported NiO was associated with reduction of the oxygen carrier to metallic Ni and Fe3O4 phases. Subsequent coke inhibition was attributed to the slow reduction of Fe3O4 and FeO phases. Multi-cyclic redox studies indicated that NiFe2O4-supported NiO gradually lost its redox activity. In comparison, both MgFe2O4- and BaFe2O4-supported NiO exhibited satisfactory redox stability, activity, and coke resistance.

Reduced Graphene Oxide-Supported Nickel(II)-Bis(1,10-Phenanthroline) Complex as a Highly Active Electrocatalyst for Ethanol Oxidation Reaction

The reduced graphene oxide (rGO) is used to support nickel(II)-bis(1,10-phenanthroline) complex (Ni(II)(Phen)2), forming a catalyst Ni(II)(Phen)2/rGO for ethanol oxidation reaction (EOR). A pyrolytic graphite electrode modified by this catalyst shows excellent electrocatalytic EOR activity, characterized by physical and electrochemical methods. The electrocatalytic activity of the material was evaluated by cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy (EIS). The significant increase in EOR currents compared to the electrode modified with only (Ni(II)(Phen)2 complex demonstrates the promotion role of the rGO. It is believed that the interaction between Ni(II)(Phen)2 and rGO to create a synergistic effect of Ni(II)(Phen)2/rGO catalyst should be responsible for the observed enhancement of the catalytic EOR performance. Using the Laviron theory, the charge transfer rate constant (ks) and the electron transfer coefficient (α) of the electrode reaction are calculated to be 0.60 s−1 and 0.61, respectively. Both the effects of OH− and ethanol concentration on the catalyst EOR activity are also studied to obtain the diffusion coefficient of ethanol (D = 4.7 × 10−6 cm2 s−1) and the catalytic rate constant (kcat = 1.26 × 107 cm3 mol−1 s−1). Based on the experimental results, an EOR mechanism catalyzed by Ni(II)(Phen)2/rGO is proposed. The catalytic EOR peak currents exhibit a linear growth (behavior) with increasing ethanol concentration, suggesting the possible use of this catalyst material as a sensor for ethanol analysis. In addition, the obtained chronoamperometric curves confirm the stability of the catalyst. It is believed that this Ni(II)(Phen)2/rGO catalyst is a promising cost-effective alternative for ethanol oxidation reaction in direct ethanol fuel cells.

Degradation of 2,4,6-trichlorophenol in synthetic wastewater by catalytic ozonation using alumina supported nickel oxides

This research aimed to investigate the efficiency of catalytic ozonation on degradation of 2,4,6-trichlorophenol (2,4,6-TCP) in synthetic wastewater. Nickel oxide doped on alumina support (NiO/Al2O3) was used as heterogeneous catalyst. Three independent variables including TCP concentration, pH, and dosage of catalysts were investigated. The results showed that efficiency on degradation of 2,4,6-TCP by using ozonation alone was 64.36% at an initial TCP concentration of 75 mg/L, pH of 4 (not adjusted), and contact time of 40 min. Degradation reaction followed the first order kinetic pattern with an apparent rate constant (kapp) of 0.025 min−1. As the pH increased to 12, the 2,4,6-TCP removal efficiency of sole ozonation increased up to 89.65%. Catalytic ozonation using NiO/Al2O3 as catalyst at a dosage of 5 g /L (equivalent to 0.25 g Ni/L) provided 2,4,6-TCP removal efficiency of 83.44% with an apparent rate constant of 0.044 min−1. Within a pH range of 4–12, the 2,4,6-TCP removal efficiencies of catalytic ozonation with NiO/Al2O3 catalyst were consistent at 84.30–86.58%. After 4 cycles of use, the 2,4,6-TCP removal efficiency reduced from 94.36% to 84.81%.

Syngas Production via Methane Dry Reforming over Ceria–Magnesia Mixed Oxide-Supported Nickel Catalysts

Dry reforming of methane (DRM) is becoming an appealing research topic because of the urgent need to minimize global warming and the demand for alternative energy resources. However, DRM commercialization and industrial scale application are limited by the deactivation of the applied catalysts. In this work, Ni-based catalysts supported on CeO2–MgO mixed oxides (0–20% CeO2 molar content) were prepared and employed in DRM. The support was synthesized via a coprecipitation method followed by impregnation of Ni metal. The catalysts prepared were characterized by X-ray diffraction, Brunauer–Emmett–Teller (BET) analysis, temperature-programmed reduction, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy (FESEM) techniques. The catalytic performance of the catalysts was evaluated in a fixed-bed continuous reactor with an equimolar (CH4/CO2) ratio at 1073 K. The addition of CeO2, as a promoter to the support, altered the interaction between Ni and MgO and modulated the properties ...

Highly stable barium zirconate supported nickel oxide catalyst for dry reforming of methane: From powders toward shaped catalysts

We report the barium zirconate supported NiOx catalysts (NiOx/BZO) for dry reforming of methane and feasibility test for their industrial application by using temperature-regulated chemical vapor deposition together with extrusion. Nickel oxide nanoparticles are well deposited and dispersed on BZO powders as well as structures in a gear form, showing high catalytic activity and extraordinary stability even at relatively lower temperature and higher space velocity. The NiOx/BZO catalyst are highly coke resistant for 50 h operation with almost negligible agglomeration of NiOx nanoparticles. Judging from XPS and high ion conducting properties of BZO supports, the –OH or –O species are expected to play an important role in promoting the self-decoking of surface carbon species to form CO and CO2.

Preparation and characterization of reduced graphene oxide supported nickel oxide nanoparticle-based platform for sensor applications

A nanostructured composite film comprising reduced graphene oxide (rGO) and nickel oxide (NiO) nanoparticles (NPs) has been prepared and utilized for development of a simple yet efficient sensor for detection of dopamine and epinephrine in a single run. The hybrid material rGO-NiO nanocomposite was synthesized chemically, and the formation of nanocomposite was confirmed via X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman, UV-Vis, and Fourier transform infrared (FTIR) spectroscopic techniques. The incorporation of NiO NPs on rGO support was found to provide improved sensing characteristics at electrode interface due to enhanced electron mobility on rGO sheet and high catalytic activity of NiO NPs. Subsequently, the synthesized rGO-NiO nanocomposite was deposited onto indium tin oxide (ITO)-coated glass substrate by simple drop-casting method, and the electrode was characterized through atomic force microscopy (AFM) and scanning electron microscopic (SEM) studies. After optimization of experimental conditions electrochemically for its high sensitivity, the fabricated rGO-NiO/ITO electrode was used for simultaneous detection of dopamine and epinephrine by square wave voltammetry (SWV) method. The results showed high sensitivity of 0.545 and 0.638 μA/μM for dopamine and epinephrine respectively in a broad linear range of 0.5–50 μM. Moreover, remarkable detection limits of 0.495 and 0.423 μM were found for dopamine and epinephrine, and the developed sensor exhibited a wide separation of 380 mV between the respective detection peaks of dopamine and epinephrine. Beside this, the proposed sensor was successfully applied in presence of high concentration of interfering agents, ascorbic acid and uric acid, and validated with real serum samples.

Mixed oxide Ti[sbnd]Si[sbnd]O prepared by non-hydrolytic Xerogel method as a diluter of nickel oxide for the oxidative dehydrogenation of ethane

Mixed TiSiO materials prepared by non-hydrolytic xerogel method have been employed as diluters for nickel oxide and used in the catalytic oxidative dehydrogenation of ethane. These catalysts have been characterized by several physicochemical techniques such as N2 adsorption, XRD, TPR, TEM, HR-TEM, and XPS. Supported nickel oxide catalysts have been reported to be efficient but only if the nature and the amount of support are controlled. In the present article it is shown that highly loaded (80wt% NiO) nickel catalysts are more efficient when diluted on mixed TiSiO materials with appropriate Ti/Si ratios than on pure TiO2 and SiO2 diluters. The catalytic results have been explained on the basis of both the crystallite size and the reducibility of NiO crystallites, as a consequence of the interaction between nickel oxide particles and metal oxides diluters. The optimal Ti/Si ratio in the diluter ensures a good dispersion of NiO because Ti4+ sites and/or very small TiO2 crystallites are highly dispersed in the surface of the matrix allowing a close contact with NiO particles. Small NiO crystallites in contact with titania are highly selective to ethylene in the oxidative dehydrogenation of ethane.

Fate of sulphur during simultaneous gasification of lignin-slurry and removal of hydrogen sulphide over calcium aluminate supported nickel oxide catalyst

The simultaneous process of synthesis gas production via lignin slurry gasification and high-temperature removal of hydrogen sulphide from the synthesis gas over calcium aluminate supported nickel oxide catalyst (NiO/CaAl2O4) was investigated. The goal of this study was to clarify the effects of the operating temperature (750–950 °C), moisture content of the lignin slurry (73–90 wt%), and catalyst loading (0.00–0.61 g-catalyst/g-feedstock) on the sulphur balance of the process and to determine the appropriate catalyst loading with cleaner biosyngas via utilisation of the sensible heat for smaller additional heat, which is maintained at the temperature of the gasifier. The biosyngas generated from gasification of lignin slurry, which contained hydrogen sulphide (H2S) and carbonyl sulphide (COS), was subjected to sulphur removal catalysed by NiO/CaAl2O4; a sulphur yield on NiO/CaAl2O4 of 0.14 mmol/g-lignin was achieved at the moisture content of 80.0 wt%, the reaction temperature of 900 °C, and the catalyst loading of 0.16 g-catalyst/g-feedstock. For the catalytic H2S removal system applicable to solid oxide fuel cells, the performance efficiency was introduced to discuss the optimal catalyst loading amount; the performance efficiency was 0.63–0.72 S-mol%·g-lignin/kJ for the catalytic operations while 0.33 S-mol%·g-lignin/kJ for non-catalytic operation.

Preparation of Cerium‐Doped Mesoporous γ‐Alumina Supported Nickel Catalysts for Pre–reforming of Liquefied Petroleum Gas under Low Steam to Carbon Ratio

AbstractCerium‐doped mesoporous γ‐alumina supported nickel oxides (NiO/Ce–γ‐MA) were prepared via one‐pot hydrolysis of inorganic salts without surfactants and applied for pre‐reforming of liquefied petroleum gas (LPG) under a low steam to carbon molar ratio of 1.2. Influences of Ce contents on catalyst structure, interaction between Ni species and support, dispersion of nickel species and Ni particle sizes were investigated in detail. The NiO/Ce–γ‐MA materials possessed large surface areas and narrow pore size distributions with homogenously‐dispersed Ni oxide species in the matrices. Upon H2 reduction, uniform Ni crystallites were formed in the γ‐alumina frameworks. The addition of Ce could significantly promote the dispersion of nickel species and lower Ni crystallite sizes, improving the catalytic properties of the reduced Ni/Ce–γ‐MA catalyst. The Ni/Ce–γ‐MA catalyst containing 7 wt% Ce produced the smallest sub‐4‐nm Ni particles, resulting in the most excellent catalytic activity and stability with less than 1 wt% carbon deposition during the 100‐h reaction time for LPG pre‐reforming.

Silicone Nanofilament Supported Nickel Oxide: A New Concept for Oxygen Evolution Catalysts in Water Electrolyzers

Supporting the evolution of oxygen: Deposition precipitation is used to decorate a carpet of silicone nanofilaments with nanostructured nickel oxide. The nanofilament support allows a decrease in the oxygen evolution overpotential in alkaline medium, and the process is of general interest for the development of binder-less electrodes. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Temperature Programmed Desorption of Carbon Dioxide for Activated Carbon Supported Nickel Oxide: The Adsorption and Desorption Studies

The priority of success in practical CO2 capture with solid sorbents is dependent on the development of a low cost sorbent and energy consumption for regeneration with high adsorption capacity. In this work, different loading of NiO were evaluated as a potential source of basic sites for CO2 capture, and activated carbon (AC) was used as a preliminary support in order to study the effect of the impregnation. The NiO loading increased the basicity of the adsorbent significantly enhance the CO2 chemisorption. Nonetheless, it drastically reduced the surface area of the AC, which is chiefly responsible for CO2 physisorption, thus decreasing the carrying capacity of ACs at room temperature and pressure.

Ethylenediamine-assisted preparation of carbon nanofiber supported nickel oxide electrocatalysts for sensitive and durable detection of insulin

Facile preparation of a carbon nanofibers/nickel oxide nanocomposite and its sensitive and durable performance for insulin electrocatalytic oxidation.

Carbon supported Pt–NiO nanoparticles for ethanol electro-oxidation in acid media

In the present work, the influence of nickel oxide as a co-catalyst of Pt nanoparticles for the electro-oxidation of ethanol in the temperature range of 23–60 °C was investigated. The carbon supported nickel oxide and platinum nanoparticles were prepared by hydrothermal synthesis and microwave-assisted polyol process respectively, and characterized by XRD, EDX, TEM and ICP analysis. The electrocatalytic activity of the as-prepared materials was studied by cyclic voltammetry and chronoamperometry. Small metal nanoparticles with sizes in the range of 3.5–4.5 nm were obtained. The nickel content in the as-prepared Pt–NiO/C catalysts was between 19 and 35 at.%. The electrochemical experiments showed that the electrocatalytic activity of the Pt–NiO/C materials increase with NiO content in the entire temperature range. The apparent activation energy (Ea,app) for the overall ethanol oxidation reaction was found to decrease with NiO content (24–32 kJ mol−1 at 0.3 V), while for Pt/C the activation energy exceeds 48 kJ mol−1. The better performance of the Pt–NiO/C catalysts compared to Pt/C sample is ascribed to the activation of both the C–H and O–H bonds via oxygen-containing species adsorbed on NiO molecules and the modification of the surface electronic structure (changes in the density of states near the Fermi level).

Reduced graphene oxide-supported nickel oxide catalyst with improved CO tolerance for formic acid electrooxidation

The superior catalytic activity along with improved CO tolerance for formic acid electrooxidation has been demonstrated on a NiO-decorated reduced graphene oxide (rGO) catalyst. The cyclic voltammetry response of rGO–NiO/Pt catalyst elucidates improved CO tolerance and follows direct oxidation pathway. It is probably due to the beneficial effect of residual oxygen groups on rGO support which is supported by FT-IR spectrum. A strong interaction of rGO support with NiO nanoparticles facilitates the removal of CO from the catalyst surface. The chronoamperometric response indicates a higher catalytic activity and stability of rGO–NiO/Pt catalyst than the NiO/Pt and unmodified Pt electrode catalyst for a prolonged time of continuous oxidation of formic acid.

Synthesis, Magnetic and Surface Properties of Reduced Graphene Oxide Supported Nickel Oxide Hybrid Nanomaterials

This study focuses on the preparation and characterization of Nickel oxide nanoparticles (NiONPs) supported on the reduced graphene oxide (r-GO) surface by a simple ultra-sonochemical method (r-GO-NiONPs). The formation of the r-GO was confirmed by FT-IR spectroscopy. The layer content of the r-GO was characterised by Raman spectroscopy. The crystalline nature and average particle size of the NiONPs were inferred by Powder-XRD spectroscopy. The surface morphology of the prepared nanoparticle was studied by the Scanning Electron Microscopy (SEM). The total surface area of the r-GO-NiONPs was ascertained by Nitrogen gas BET adsorption isotherm. Surface area of r-GO-NiONPs is 282 m2g-1 which is little over twice of Graphene Oxide (GO) 132 m2g-1. The magnetic properties of the prepared r-GO-NiONPs was studied using Vibrating Sample Magnetometer (VSM). Field dependent magnetization studies of r-GO-NiONPs delivers a very promising result.

Three-dimensional carbon nanotube networks with a supported nickel oxide nanonet for high-performance supercapacitors.

A three-dimensional porous carbon nanotube film with a supported NiO nanonet was prepared by simple electrophoretic deposition and hydrothermal synthesis, which could deliver a high specific capacitance of 1511 F g(-1) at a high discharge current of 50 A g(-1) due to the significantly improved transport of the electrolyte and electrons.

Effects of Silica-Supported Nickel and Vanadium on Liquid Products of Catalytic Steam Pyrolysis of Biomass

Catalytic steam pyrolysis of biomass was performed in a bubbling fluidized-bed reactor at 450 °C, and the effects of silica-supported transition metals (Ni and V) on product yields and compositions have been investigated. Both metals seem to be catalytically active and altered the liquid composition. An interesting finding is the in situ reduction of the supported nickel oxide to metallic Ni during the pyrolysis reactions, which can enhance H-transfer. Vanadia-containing catalysts show higher selectivity in reduction of carboxylic acids and ketones. An increased aldehyde content, especially for the bimetallic Ni–V catalyst, suggests that selective deoxygenation can take place via the Mars van Krevelen (MvK) mechanism. Ni catalysts showed activity for aromatics formation, while both metals showed selectivity in producing phenols instead of catechols. Assessment of the catalytic performance indicates that both metals could be interesting candidates for incorporation in other support materials and evaluation...

Kinetics of hydrodeoxygenation of stearic acid using supported nickel catalysts: Effects of supports

The hydrodeoxygenation of fatty acids derived from vegetable and microalgal oils is a novel process for production of liquid hydrocarbon fuels well-suited with existing internal combustion engines. The hydrodeoxygenation of stearic acid was investigated in a high pressure batch reactor using n-dodecane as solvent over nickel metal catalysts supported on SiO2, γ-Al2O3, and HZSM-5 in the temperature range of 533–563K. Several supported nickel oxide catalysts with nickel loading up to 25wt.% were prepared by incipient wetness impregnation method and reduced using hydrogen. The catalysts were then characterized by BET, TPR, H2 pulse chemisorption, TPD, XRD, and ICP-AES. Characterization studies revealed that only dispersed nickel oxide was present up to 15wt.% nickel loading on γ-Al2O3. The acidity of the supports depends on nickel loading of oxidized catalysts and increases with increasing nickel loading up to 15wt.%. n-Pentadecane, n-hexadecane, n-heptadecane, n-octadecane, and l-octadecanol were identified as products of hydrodeoxygenation of stearic acid with n-heptadecane being primary product. The catalytic activity and selectivity to products for hydrodeoxygenation of stearic acid depends strongly on acidity of the supports. The maximum selectivity to n-heptadecane was observed with nickel supported γ-Al2O3 catalyst. A suitable reaction mechanism of hydrodeoxygenation of stearic acid was delineated based on products distribution. The conversion of stearic acid was increased with increasing reaction time, nickel loading on γ-Al2O3, temperature, and catalyst loading. Complete conversion of stearic acid was accomplished with more than 80% selectivity to n-heptadecane at reasonable reaction temperature of 563K after 240min of reaction using 15wt.% Ni/γ-Al2O3 catalyst. An empirical kinetic model was also developed to correlate the experimental data.

Thermally reduced graphene oxide-supported nickel catalyst for hydrogen production by propane steam reforming

Pristine (GO) and thermally reduced graphene oxide (TRGO)-supported nickel catalysts were prepared by a deposition–precipitation (DP) method with a constant loading amount of 20wt% Ni. According to the nature of the GO and TRGO supports, nickel catalysts with different morphologies were formed on the graphene supports. The prepared samples were characterized by BET surface area, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses. The morphological characterization studies revealed the formation of plate-like particles in the TRGO supports, whereas spherical particles were obtained by decorating the GO with nickel nanoparticles. The performance of the synthesized catalysts in the steam reforming of propane was compared to the performance of a nickel over alumina (Ni-Al2O3) commercial catalyst (FCR4, Sud-chem, USA). Ni-TRGO showed the best results in terms of H2 conversion when compared to the Ni-GO and commercial catalysts. The results revealed that the amount of the Ni0 state, metal dispersion, and particle size played main roles in the catalyst performance, rendering Ni-TRGO as the most promising among the catalysts studied for the steam reforming of propane.