• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.714-722
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• 2019

Catalysts were prepared by using incipient wetness impregnation method with 17 wt% Ni on a support ($SiO_2-Y_2O_3$, $Al_2O_3$, $SiO_2-ZrO_2$, $SiO_2$, $TiO_2$, MgO) and the catalytic activity in the reductive amination of ethanol with ammonia in the presence of hydrogen was compared and evaluated. The catalysts used before and after the reaction were characterized using X-ray diffraction, nitrogen adsorption, ethanol-temperature programmed desorption (EtOH-TPD), isopropanol-temperature programmed desorption (IPA-TPD), and hydrogen chemisorption etc. In the case of preparing $ZrO_2$ and $Y_2O_3$ supports, the small amount of Si dissolution from the Pyrex reactor surface provoked the formation of mixed oxides $SiO_2-ZrO_2$ and $SiO_2-Y_2O_3$. Among the catalysts used, $Ni/SiO_2-Y_2O_3$ catalyst showed the best activity, and this good activity was closely related to the highest nickel dispersion, and low desorption temperature in EtOH-TPD and IPA-TPD. The low catalytic activity on Ni/MgO catalysts showed low activity due to the formation of NiO-MgO solid-solutions. In the case of $Ni/TiO_2$, the reactivity was low due to the low nickel metal phase due to strong metal-support interaction. In the case of using a support as $SiO_2-Y_2O_3$, $Al_2O_3$, $SiO_2-ZrO_2$, and $SiO_2$, the selectivities of ethylamines and acetonitrile were not significantly different at similar ethanol conversion.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.683-692
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• 2009

The synthesis of a novel series of nickel(II) complexes with new ligands derived from hydrazones of isoniazid have been reported in present work. The complexes have general compositions [$Ni(L)_2X_2$] or $[Ni(L)_3](ClO_4)_2$ {L = N-isonicotinamido-furfuraldimine (INH-FFL), N-isonicotinamido-3',4',5'-trimethoxybenzaldimine (INH-TMB) or N-isonicotinamido-cinnamalidene (INH-CIN) and X = $Cl^-$, ${NO_3}^-$, $ NCS^-$ or $CH_3COO^-$}. The ligands hydrazones behave as neutral bidentates (N and O donor) through the carbonyl oxygen and azomethine nitrogen. The new complexes with octahedral geometry have been characterized by elemental analysis, molecular weight determinations, magnetic susceptibility/moment, thermogravimetric, electrochemical and spectroscopic studies viz. infrared and electronic spectra. On the basis of conductivity measurements in nitrobenzene ($PhNO_2$) solution the [$Ni(L)_2X_2$] and $[Ni(L)_3](ClO_4)_2$ complexes have been found to be non-electrolytes and 1:2 electrolytes, respectively. Thermal properties have also been investigated, which support the geometry of the complexes. Antibacterial and antifungal properties of nickel(II) complexes and few standard drugs have also been examined and it has been observed that the complexes have moderate antibacterial activities.

• Clean Technology
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• v.29 no.3
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• pp.163-171
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• 2023

Hydrogen has been gaining a lot of attention as a possible clean energy source that can aid in reaching carbon neutrality. Currently, hydrogen production has relied on the steam reforming of fossil fuels. However, due to the carbon dioxide emissions caused by this process, hydrogen production based on the steam reforming of bio-oil derived from biomass has been proposed as an alternative approach. In order to use this alternative approach efficiently, one of the key issues that must be overcome is that the complexity of bio-oil, which has a large molecular weight and diverse functional groups of hydrocarbons, promotes the catalytic deactivation of nickel-based catalysts. In this review, research efforts to improve nickel-based catalysts for the steam reforming of bio-oil have been discussed in terms of the active phase, support, and promoters. The active phases are involved in activating C-C and C-H bonds of high-molecular-weight hydrocarbons, and noble and transition metals can be utilized. In terms of the support and promoters, the catalytic deactivation of Ni-based catalysts can be inhibited by utilizing reactive lattice oxygen for support or by suppressing the acidity. The development of active and stable Ni-based reforming catalysts plays a critical role in clean hydrogen production based on bio-oils.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2154-2159
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• 2007

The potential of using a double-faced wall stagnation flow burner in mass production of carbon nanotubes was evaluated experimentally and computationally. With nitrogen-diluted premixed ethylene-air flames established on the Nickel-coated stainless steel double-faced wall, the propensities of carbon nanotube formation were experimentally determined using SEM and FE-TEM images and Raman spectroscopy, while the flame structure was computationally predicted using a 3-dimensional CFD code with a reduced reaction mechanism. The uniformity and yields of synthesized carbon nanotubes were evaluated in terms of the flame stretch rates. Results show substantial increase of area on the wall surface where uniform carbon nanotubes are synthesized with using the double-faced wall stagnation flow burner due to enhanced uniformity of temperature distribution along the wall surface and support the potential of using a double-faced wall stagnation flow burner in mass production of carbon nanotubes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.3 s.246
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• pp.349-355
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• 2006

The gas turbine components is used on high temperature conditions which under severely circumstance with start-up and stop several times. Therefore, it is used nickel-base superalloys like and GTD-111DS. Damaged buckets on the t긴ade tip during operating are repaired per 24,000 hr to three times according to repair specification of manufacture. It is applied pre-heat, HIP(hot isostatic pressing) and post-heat treatment to support welding repair on blade tip effectively. On this study, It is utilize of $WRAP^{TM}$ (welding repair advanced process) method to make tension test specimens for this study, And then, material strength and characteristic for GTD-111DS was analyzed.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.402.1-402.1
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• 2016

The performance of solid oxide fuel cells (SOFCs) is directly related to the electrocatalytic activity of composite electrodes in which triple phase boundaries (TPBs) of metallic catalyst, oxygen ion conducting support, and gas should be three-dimensionally maximized. The distribution morphology of catalytic nanoparticle dispersed on external surfaces is of key importance for maximized TPBs. Herein in situ grown nickel nanoparticle onto the surface of fluorite oxide is demonstrated employing gadolium-nickel co-doped ceria ($Gd0.2-xNixCe0.8O2-{\delta}$, GNDC) by reductive annealing. GNDC powders were synthesized via a Pechini-type sol-gel process while maximum doping ratio of Ni into the cerium oxide was defined by X-ray diffraction. Subsequently, NiO-GNDC composite were screen printed on the both sides of yttrium-stabilized zirconia (YSZ) pellet to fabricate the symmetrical half cells. Electrochemical impedance spectroscopy (EIS) showed that the polarization resistance was decreased when it was compared to conventional Ni-GDC anode and this effect became greater at lower temperature. Ex situ microstructural analysis using scanning electron microscopy after the reductive annealing exhibited the exsolution of Ni nanoparticles on the fluorite phases. The influence of Ni contents in GNDC on polarization characteristics of anodes were examined by EIS under H2/H2O atmosphere. Finally, the addition of optimized GNDC into the anode functional layer (AFL) dramatically enhanced cell performance of anode-supported coin cells.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.5
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• pp.599-608
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• 2011

The Ni-Al anodes of the molten carbonate fuel cell (MCFC) with three different structures were successfully fabricated in order to reduce the thickness of the anode down to 0.3 mm; one was the non-supported anode made by a conventional tape casting method, and others were the supported anodes made by lamination or direct casting on the nickel screen. It was seen from the physical analyses and cell operation that the supported thin anodes made by direct casting showed good mechanical strength and cell performance because of a good contact between the anode materials and the support. The single cell using the above anode showed the cell voltage of 0.858 V at the current density of 150$mA/cm^2$ with the nitrogen cross-over of only 0.6% at the operation time of 1,000 h, which was similar to the performance of the conventional thick (0.7 mm) anode. The ability to utilize a thin configuration of anode should cut down the amount of nickel alloy and consequently reduce its manufacturing cost.

• Carbon letters
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• v.11 no.1
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• pp.38-40
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• 2010

Carbon supported electrocatalysts are commonly used as electrode materials for polymer electrolyte membrane fuel cells(PEMFCs). These kinds of electrocatalysts provide large surface area and sufficient electrical conductivity. The support of typical PEM fuel cell catalysts has been a traditional conductive type of carbon black. However, even though the carbon particles conduct electrons, there is still significant portion of Pt that is isolated from the external circuit and the PEM, resulting in a low Pt utilization. Herein, new types of carbon materials to effectively utilize the Pt catalyst are being evaluated. Carbon nanofiber/activated carbon fiber (CNF/ACF) composite with multifunctional surfaces were prepared through catalytic growth of CNFs on ACFs. Nickel nitrate was used as a precursor of the catalyst to synthesize carbon nanofibers(CNFs). CNFs were synthesized by pyrolysising $CH_4$ using catalysts dispersed in acetone and ACF(activated carbon fiber). The as-prepared samples were characterized with transmission electron microscopy(TEM), scanning electron microscopy(SEM). In TEM image, carbon nanofibers were synthesized on the ACF to form a three-dimensional network. Pt/CNF/ACF was employed as a catalyst for PEMFC. As the ratio of prepared catalyst to commercial catalyst was changed from 0 to 50%, the performance of the mixture of 30 wt% of Pt/CNF/ACF and 70wt% of Pt/C commercial catalyst showed better perfromance than that of 100% commercial catalyst. The unique structure of CNF can supply the significant site for the stabilization of Pt particles. CNF/ACF is expected to be promising support to improve the performance in PEMFC.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.458-464
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• 2006

The Pd-Ni-Ag alloy composite membrane using modified porous stainless steel (PSS) as a substrate was prepared by a electroless plating technique. In this work, we have introduced the intermediate layer between Pd-based alloy and a metal substrate. As an intermediate layer, the mixtures of nickel powder and inorganic sol such as $SiO_{2}$ sol, $Al_{2}O_{3}$ sol, and $TiO_{2}$ sol were used. The intermediate layers were coated onto a PSS substrate according to various membrane preparation conditions and then $N_{2}$ fluxes through the membranes with different intermediate layers were measured. The surface morphology of the intermediate layer in the mixture of nickel powder and inorganic sol was analyzed using scanning electron microscope (SEM). Finally, the Pd-Ni-Ag alloy composite membrane using the support coated with the mixture of nickel powder and silica as an intermediate layer was fabricated and then the gas permeances for $H_{2}$ and $N_{2}$ through the Pd-based membrane were investigated. The selectivity of $H_2/N_2$ was infinite and the $H_{2}$ flux was $1.39{\times}10^{-2}mol/m^2{\cdot}s$ at the temperature of $500^{\circ}C$ and trans-membrane pressure difference of 1 bar.

• Clean Technology
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• v.25 no.2
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• pp.101-106
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• 2019

The aim of this study is to investigate the feasibility of an Ni-SA catalyst, which was prepared from nickel, kieselguhr, and alumina, for the hydrogenation of triglyceride in a bench-scale reactor. Ni-SA powders were prepared by precipitating nickel precursors on a silica and alumina support. The powder was reduced in a hydrogen flow, mixed with a saturated palm oil, and then cooled to prepare an Ni-SA catalyst tablet. The sizes of NiO crystals of a commercial Pricat catalyst and the Ni-SA catalyst prepared in this study were $35{\AA}$ and $38{\AA}$, respectively. The pore volume and pore size of the Ni-SA catalyst was much larger than the pore volume and pore size of the Pricat catalyst. In addition, the average particle size of the Ni-SA catalyst was much smaller than that of the Pricat catalyst. The triglyceride hydrogenation reaction was carried out in a semi-batch reactor using catalysts impregnated with oil and molded into tablets. It was found that the Ni-SA catalyst was superior to the commercial Pricat catalyst in triglyceride hydrogenation, which could be ascribed to the raw material and the products being less influenced by the diffusion resistance in the pores of the Ni-SA catalyst. The Ni-SA catalyst prepared in this study has the potential to replace the Pricat catalyst as a catalyst for use in the commercial process for hydrogenation of triglyceride.