Nickel-based Oxide Research Articles

High-efficient removal of oxygen (O2) impurity from hydrogen (H2) flow on nickel-based oxide: effect of metal dopants

Hydrogen is considered as a green energy source, which has attracted widespread attention. Electrocatalytic hydrogen production is a promising technology for generating clean hydrogen. However, the by-product oxygen in this process would lead to a risk of explosion that should be removed before using. In this work, nickel-based oxides doped with variable proportions of Mn, Co, and Cu were used for oxygen removal through catalytic oxidation technology. The catalytic test results show that the optimized catalysts, including 4NiMn, 2Ni1.5Co, and NiCu exhibit better performance. Among all the catalysts, 4NiMn catalyst has the best catalytic performance, achieving a 90% oxygen removal rate below 100 °C. According to the results of H2-TPR, O2-TPD and H2-TPD, the catalysts with better deoxidation effect (4NiMn, 2Ni1.5Co and NiCu) exhibit a stronger oxidation-reduction ability. 4NiMn has higher amounts of adsorption surface oxygen species and overflow hydrogen, which are key factors of the promoting deoxidation effect. Overall, it can be concluded that the optimal catalytic performance of 4NiMn can be attributed to its ability to better adsorb oxygen on its surface, promote the release of overflow hydrogen and participate in oxidation-reduction reactions.

Revealing the Electro-oxidation Mechanism of 5-Aminotetrazole on Nickel-Based Oxides and Synthesizing 5,5'-Azotetrazolate Salts.

With the gradual expansion of the application of organic electromechanical synthesis in the field of energetic materials, it is necessary to explore deeply the mechanisms behind the organic electromechanical oxidation of energetic materials in order to develop efficient electrocatalysts. Electrochemical synthesis of 5,5'-azotetrazolate (ZT) salts is not only environmentally friendly and efficient but also can replace oxygen evolution reaction (OER) combined with hydrogen production, significantly reducing the battery voltage of overall water splitting (OWS) and achieving low energy consumption hydrogen production. Here, we prepared the Co-modified nickel-based oxide electrodes (Ni3-xCoO4/carbon cloth (CC), x = 1, 2) as a medium to reveal the oxidative coupling mechanism of 5-aminotetrazole (5-AT). Experimental and theoretical calculations verified that Ni-catalyzed oxidative coupling of 5-AT is a proton-coupled electron transfer (PCET) process, including electron transfer of electrocatalytic intermediates (Ni2+-O + OH- = Ni3+-O(OH) + e-) and spontaneous dehydrogenation process (Ni3+-O(OH) + X-H = Ni2+-O + X•). The Ni3+-O(OH) is an extremely fast nonreducing electron transfer center that serves as a chemical oxidant to directly abstract hydrogen atoms from the 5-AT. Simultaneously, the synergistic effect of Co doping on the electric cloud around Ni causes the upshift of the d-band centers, which is conducive to the easier adsorption of OH*, forming the generation of active intermediate Ni3+-O(OH). Thus, Ni2CoO4/CC has higher Faraday efficiency (FE) and yield for the oxidation reaction of 5-AT, with a yield of approximately 72.3% after electrolysis at 1.7 V vs reversible hydrogen electrode (RHE).

Flow behaviors and microstructural evolutions of nickel-based ODS superalloys during hot deformation

The hot deformation behaviors of nickel-based oxide dispersion strengthened (ODS) superalloys fabricated by mechanical alloying (MA) and hot extrusion (HEX) were investigated, the hot compression tests were performed to obtain true stress-true strain curves, the influence of strain rate and temperature connected with the microstructure evolution was analyzed, and the processing map and microstructure proposed at different strain levels was used to select its hot working parameters. The results illustrated that hot working conditions, especially the temperature, strongly influenced the grain structure. Specifically, deforming under high temperatures and low strain rate conditions enhances dynamic softening via dynamic recovery (DRV), dynamic recrystallization (DRX), and grain growth to consume the stored strain energy. In addition, the size and morphology of nanoparticles are not significantly changed before and after deformation, the nanoparticles and the matrix still maintain a good interface combination, and no interfacial mismatch such as nanosvoids between the nanoparticle and matrix is detected due to their outstanding interfacial binding ability and excellent ductility of matrix.

Investigation on different additions as candidates for nano-oxide particles in nickel-based ODS superalloys

Four nickel-based oxide dispersion strengthened (ODS) superalloys with the additions of YH2, Y2O3, La2O3 and CeO2 (denoted as ODS-Y1 ODS-Y2, ODS-La and ODS-Ce) are prepared, respectively. The tensile tests at temperatures ranging from room temperature (RT) to 1000 °C were conducted on them. In this work, by means of microstructure characterization and theoretical modeling, different strengthening mechanisms including grain boundary strengthening, solution strengthening, dislocations and dispersion strengthening, were estimated to contribute to the yield strength in different degrees, which would help to further enhance the tensile properties of alloys through nanoparticles optimization thereafter, and the formation and evolution mechanism of nanoparticles are discussed. The results show that ODS-Y1 has the smallest particles and the best comprehensive mechanical property in the tested alloys. The nanoparticles having M-Al-rich (M = Y, La, Ce) cores and Ti-O-rich shells structure are observed in nickel-based ODS superalloys, and the M-Al-O are preferentially formed, due to the higher diffusion rate of Al atom and high M/Al value. Then Ti and O atoms diffuse to the surface of nanoparticles, forming a core-shell structures in the later precipitation stages.

Data-driven optimal closures for mean-cluster models: Beyond the classical pair approximation.

This study concerns the mean-clustering approach to modeling the evolution of lattice dynamics. Instead of tracking the state of individual lattice sites, this approach describes the time evolution of the concentrations of different cluster types. It leads to an infinite hierarchy of ordinary differential equationswhich must be closed by truncation using a so-called closure condition. This condition approximates the concentrations of higher-order clusters in terms of the concentrations of lower-order ones. The pair approximation is the most common form of closure. Here, we consider its generalization, termed the "optimal approximation," which we calibrate using a robust data-driven strategy. To fix attention, we focus on a recently proposed structured lattice model for a nickel-based oxide, similar to that used as cathode material in modern commercial Li-ion batteries. The form of the obtained optimal approximation allows us to deduce a simple sparse closure model. In addition to being more accurate than the classical pair approximation, this "sparse approximation" is also physically interpretable which allows us to a posteriori refine the hypotheses underlying construction of this class of closure models. Moreover, the mean-cluster model closed with this sparse approximation is linear and hence analytically solvable such that its parametrization is straightforward, although it offers a good approximation of the actual time evolution of the cluster concentrations on short timescales only. On the other hand, parametrization of the mean-cluster model closed with the pair approximation is shown to lead to an ill-posed inverse problem.

Optimizing the Thermomechanical Process of Nickel-Based ODS Superalloys by an Efficient Method.

Thermo-mechanical process of nickel-based oxide dispersion strengthened (ODS) superalloys is critical to produce desired components. In this study, an efficient method of consolidating powder is introduced to optimize the preparation process, microstructure and properties of nickel-based ODS superalloys. The influences of consolidation temperature, strain rate and ball milling time on the hardness of nickel-based superalloys were studied. The relationship among process, microstructure and hardness was established, the nanoparticles strengthening and grain boundary strengthening in nickel-based ODS superalloys were discussed. The results indicate that long ball milling time, moderately low consolidation temperature and high strain rates are beneficial to improving properties of nickel-based superalloys. Moreover, dispersion strengthening of nanoparticles and grain boundary strengthening play important roles in enhancing nickel-based ODS superalloys.

Development of Ni-base oxide dispersion strengthened alloys using yttria-stabilised zirconia nanoparticles: powder preparation and spark plasma sintering processing

ABSTRACT In the present study, nickel-based oxide dispersion strengthened (ODS) alloys were prepared by mechanical alloying (MA) andspark plasma sintering (SPS) using the yttria-stabilised zirconia (YSZ) nanoparticle was used as the oxide additive. Then, the powder samples and consolidated ODS parts were examined using XRD, SEM, and mechanical properties of samples were investigated. The results showed, the lattice strain increases to about 0.461%, indicating that the misalignment density in the particles has risen sharply due to MA. XRD results showed that peak flattening was observed with increasing alloying time to 5 and 10 h. The measured relative density of the parts is 96–98%. The secondary phase in the microstructure was the carbide phase of type M7C3 and MC with an average size mainly less than 5 μm. The highest tensile strength observed in Mo/W containing alloy, which was much higher than conventional alloys such as IN738 and IN939.

Towards development of a nickel-based oxide dispersion strengthened alloy for use in Molten Salt reactors.

Towards development of a nickel-based oxide dispersion strengthened alloy for use in Molten Salt reactors.

Preparation of Copper and Nickel-Based Oxide Self-Supporting Electrode by Electrochemical Etching Method for the Detection of Glucose

It is of great significance to prepare electrochemical glucose sensors with high selectivity and stability via effective and rapid methods. In this work, the self-support electrode with copper and nickel-based oxide is prepared by chemical-etching reaction which occurred under the property of electrochemical potential difference. In this processing, nickel foam is etched selectively by Cu[Formula: see text] ions and they not only act as self-supporting electrode substrate, but also as nickel ions precursor of NiO. Moreover, the reaction can be completely satisfied on 30 min at room temperature. As a self-supporting electrode nonenzymic glucose electrochemical sensor, the electrode exhibited a wide linear range (0.04–3.00[Formula: see text]mM), low detection limit (0.02[Formula: see text]mM) with high sensitivity of 1096[Formula: see text][Formula: see text] and good selectivity, repeatability and stability. Furthermore, the application of the prepared sensor provides an avenue for the application of the transition metal materials in the field of electrochemical sensing.

Recent Progress on Nickel-Based Oxide/(Oxy)Hydroxide Electrocatalysts for the Oxygen Evolution Reaction.

Developing clean and sustainable energies as alternatives to fossil fuels is in strong demand within modern society. The oxygen evolution reaction (OER) is the efficiency-limiting process in plenty of key renewable energy systems, such as electrochemical water splitting and rechargeable metal-air batteries. In this regard, ongoing efforts have been devoted to seeking high-performance electrocatalysts for enhanced energy conversion efficiency. Apart from traditional precious-metal-based catalysts, nickel-based compounds are the most promising earth-abundant OER catalysts, attracting ever-increasing interest due to high activity and stability. In this review, the recent progress on nickel-based oxide and (oxy)hydroxide composites for water oxidation catalysis in terms of materials design/synthesis and electrochemical performance is summarized. Some underlying mechanisms to profoundly understand the catalytic active sites are also highlighted. In addition, the future research trends and perspectives on the development of Ni-based OER electrocatalysts are discussed.

Fabrication and Characterization of Additive Manufactured Nickel-Based Oxide Dispersion Strengthened Coating Layer for High-Temperature Application

Increasing turbine inlet temperature is important for improving the efficiency of gas turbine engine. Elevated thermal load causes severe oxidation and corrosion for base alloy in turbine airfoils. To survive in this extreme high-temperature and harsh oxidation environment, both outside protection like thermal barrier coatings (TBC) and inside air cooling have been applied to turbine blades. Significantly more protection can be achieved if the cooling channels are embedded near surface, constructed partially by the coating system and partially by the superalloy substrate. However, neither the ceramic coating layer nor the metallic bond coating layer in current TBC system can provide structural support to such internal cooling channels. Development of structural bond coating layers consequently becomes one of the key technologies to achieve this goal. The present study proposed a method to fabricate structural coating layers on top of turbine blades with the aid of additive manufacturing (AM) and oxide dispersion strengthened (ODS) nickel-based alloy. ODS powder comprised of evenly distributed host composite particles (Ni, Al, Cr) with oxide coating layers (Y2O3) was subjected to a direct metal laser sintering (DMLS) process to fabricate a desirable structural coating layer above nickel-based superalloy substrates. Systematic experimental tests were carried out focusing on the interface adhesion, mechanical strength, microstructure, and surface finish of the ODS coating layer. Based on characterization results from indentation tests and microscopy observations, an optimal coating quality was obtained under ∼250 W laser power. The selected samples were then characterized under isothermal conditions of 1200 °C for 2000 h. Scanning electron microscope (SEM) observations and energy-dispersive X-ray spectroscopy (EDX) analysis were conducted in different stages of the oxidation process. Results indicated a formation of Al2O3 scale on top of the ODS coating layer at early stage, which showed long-term stability throughout the oxidation test. The formation of a stable alumina scale is acting as a protective layer to prevent oxygen penetrating the top surface. Spallation of part of nickel oxide and chromium oxide is observed but the thickness of oxide scale is almost no change. In addition, the observed adhesion between ODS coating layer and substrate was tight and stable throughout the entire oxidation test. The present study has provided strong proof that additive manufacturing has the capability to fabricate structural and protective coating layers for turbine airfoils.

Two-Dimensional Cobalt-/Nickel-Based Oxide Nanosheets for High-Performance Sodium and Lithium Storage.

Two-dimensional (2D) nanomaterials are one of the most promising types of candidates for energy-storage applications due to confined thicknesses and high surface areas, which would play an essential role in enhanced reaction kinetics. Herein, a universal process that can be extended for scale up is developed to synthesise ultrathin cobalt-/nickel-based hydroxides and oxides. The sodium and lithium storage capabilities of Co3 O4 nanosheets are evaluated in detail. For sodium storage, the Co3 O4 nanosheets exhibit excellent rate capability (e.g., 179 mA h g-1 at 7.0 A g-1 and 150 mA h g-1 at 10.0 A g-1 ) and promising cycling performance (404 mA h g-1 after 100 cycles at 0.1 A g-1 ). Meanwhile, very impressive lithium storage performance is also achieved, which is maintained at 1029 mA h g-1 after 100 cycles at 0.2 A g-1 . NiO and NiCo2 O4 nanosheets are also successfully prepared through the same synthetic approach, and both deliver very encouraging lithium storage performances. In addition to rechargeable batteries, 2D cobalt-/nickel-based hydroxides and oxides are also anticipated to have great potential applications in supercapacitors, electrocatalysis and other energy-storage-/-conversion-related fields.

Reduction of High Nickel-Based Oxide Particles Using Hydrogen Gas

Oxide particles of Fe-77Ni alloy scraps were reduced by hydrogen gas on the effect of temperature and time. The chemical composition of metallic powder was examined by X-ray diffraction (XRD) and FeNi3 alloy was finally obtained with a mean particle size of 10μm.

Layered Nickel-Based Oxides on Partially Oxidized Metallic Copper Foils for Lithium Ion Batteries

ABSTRACT: Thin film electrodes have been intensively studied for active materials and current collectors toenhance the electrochemical performance. Here, porous structures of nickel-based oxide films, con-sisting of nickel oxide and copper (II) oxide, which was derived from the copper substrate duringthe annealing process, were deposited on metallic copper foils. The half-cell tests revealed excellentcapacity retention after 80 th charge/discharge cycles. Some films showed an excess of the theoret-ical capacity of nickel oxides, which mainly originate from partially oxidized copper substrates dur-ing annealing. These results exhibit that both a preparation method of an active materials andpartially oxidized current collectors could be important roles to apply thin film electrodes.Keywords : Nickel Oxides, Copper Oxides, Current Collectors, Anode, Lithium Ion Batteries Received December 3, 2011 : Accepted December 27, 2011 1. Introduction The decreasing size of electronic devices has focusedincreasing attention on thin film batteries as an on-chippower supplier. Like the general types of lithium ionbatteries, thin film batteries use an anode and cathode.In particular, the anode is composed of a current collec-tor and an active material that reacts with lithium ionsdirectly. Most preliminary approaches focused on cur-rent collectors

Comparison of the surface changes on cathode during long term storage testing of high energy density cylindrical lithium-ion cells

Nickel-based oxide cathode material taking out from lithium-ion cell after storage for 2 years at 45 °C is analyzed by electron energy-loss spectroscopy in a scanning transmission electron microscope (STEM-EELS) and the result of STEM-EELS is compared with cobalt-based oxide cathode material which is treated as same manor as nickel-based oxide cathode material. The Ni-L 2,3 energy-loss near-edge structure (ELNES) spectra of nickel-based oxide cathode material show peak positions similar to original material before storage. This result indicates that nickel-based oxide material has no significant change in the surface structure. On the other hand, a remarkable shift to low energy is observed in the Co-L 2,3 ELNES spectra of the cobalt-based oxide cathode material after storage. The cycle test at 60 °C under the conditions of aggressive driving cycle (US06) mode for the nickel-based oxide cathode/graphite cell is also carried out. It is clear that cycle performance of the nickel-based oxide cathode/graphite cell is dependent on the depth of discharge (DOD).

Recrystallization Behavior of the Nickel-Based ODS Superalloy PM 1000

PM 1000 is a nickel-based oxide dispersion strengthened (ODS) superalloy used for high-temperature applications. The primary recrystallization of a <100>-fiber textured coarsegrained oxide dispersion strengthened nickel-based superalloy (PM 1000) has been investigated. The annealing behavior of this alloy is quite complex. Even when annealing is performed at high homologous temperatures (e.g. 0.9 Tm, Tm is the melting point), recrystallization is partial. In order to understand such a behavior, the microstructure of specimens in both the as-received, deformed, and annealed conditions has been imaged in detail using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution electron backscatter diffraction (EBSD). In the annealed state we observe a significant volume fraction of tiny crystals in the interior of the recovered grains. These tiny grains are elongated and grow mostly along the existing low angle dislocation boundaries (anisotropic growth). In the present paper we propose a twinningassisted nucleation mechanism to clarify their origin during recrystallization.

Cobalt and tantalum additions for enhanced electrochromic performances of nickel-based oxide thin films grown by pulsed laser deposition

Aiming at improving the durability of anodic electrochromic nickel oxide thin films, Ni–M–O (M = Co, Ta) thin films were grown by pulsed laser deposition (PLD), using optimized conditions, namely room temperature and 10 −1 mbar oxygen pressure. For low Co and Ta contents (<5%), both additions lead to a loss of the [1 1 1] preferred orientation of the NiO rock-salt structure followed by a film amorphization with increasing Ta amount. Among the two series of metal additions (M ≤ 20%), the Ni–Co–O (5% Co) and Ni–Ta–O (10% Ta) thin films show the highest electrochemical performances especially in respect of improved durability. If the enhanced properties are associated with a limited dissolution of the oxidized phase for the Ni–Ta–O system, the opposite trend is observed for the Ni–Co–O system as compared to pure NiO.