• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.63-66
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• 2007

Reformers which produce hydrogen from natural gas are essential for the operation of residential PEM fuel cells. For this purpose, steam-methane reforming reactions with Ni catalysts is primarily utilized. Commercial Ni catalysts are generally made to have porous pellet shapes in which Ni catalyst particles are uniformly dispersed over Alumina support structures. This study numerically investigates the reduction of catalyst effectiveness due to the mass transport resistances posed by porous structures of spherical catalyst pellets. The multi-component diffusion through porous media and the accurate kinetics of reforming reaction is fully considered in the numerical model. The preliminary results on the variation of the effectiveness factor according to different operation conditions are presented, which is planned to be used to develop correlations in future studies.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.266-266
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• 2012

Ni films with a thickness of 700-800 nm were deposited on carbon fiber layers using electroless deposition, and surface structures and chemical properties of these films with various annealing temperatures (300, 600 and $900^{\circ}C$) were studied. $600^{\circ}C$-annealing under atmospheric conditions resulted in formation of porous surface structures with a mean pore size of ~100 nm, whereas the other samples showed non-porous surface structures. $600^{\circ}C$-annealed Ni film showed much higher reactivities for toluene adsorption and CO oxidation comparing to other non-porous surfaces.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.438-442
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• 2013

In the present work, electroless plating was used for coating thin films consisting mainly of Ni and P on carbon fiber. Structural changes appeared upon the post-annealing at various temperatures of the Ni-P film on carbon fiber was studied using various analysis methods. Scanning, a flat surface structure of Ni-P film on carbon fiber was found after electroless plating of Ni-P film on carbon fiber without post-annealing, whereas annealing at $350^{\circ}C$ resulted the formation of porous structures. With increasing the annealing temperature to $650^{\circ}C$ with an interval of $50^{\circ}C$, the pore size increased, but the density decreased. X-ray diffraction (XRD) showed the existence of metallic Ni, and Ni-P compounds before post-annealing, whereas the post-annealing resulted in the appearance of NiO peaks, and the decrease in the intensity of the peak of metallic Ni. Using X-ray photoelectron spectroscopy (XPS), phosphorous oxides were detected on the surface upon annealing at $650^{\circ}C$, and $700^{\circ}C$, which can be attributed to the phosphorous compounds originally existing in the deeper layers of the Ni films, which undergo sublimation and escape from the film upon annealing. Escape of phosphorous species from the bulk of Ni-P film upon annealing could leave a porous structure in the Ni films. Porous materials can be of potential applications in diverse fields due to their interesting physical properties such as high surface area, and methods for fabricating porous Ni films introduced here could be easily applied to a large-scale production, and therefore applicable in diverse fields such as environmental filters.

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.1
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• pp.41-52
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• 2021

NiO and Co3O4-doped porous La(CoNi)O3 perovskite oxides were prepared from excess Ni addition by a hydrothermal method using porous silica template, and characterized as bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) for Zn-air rechargeable batteries in alkaline solution. Excess Ni induced to form NiO and Co3O4 in La(CoNi)O3 particles. The NiO and Co3O4-doped porous La(CoNi)O3 showed high specific surface area, up to nine times of conventionally synthesized perovskite oxide, and abundant pore volume with similar structure. Extra added Ni was partially substituted for Co as B site of ABO3 perovskite structure and formed to NiO and Co3O4 which was highly dispersed in particles. Excess Ni in La(CoNi)O3 catalysts increased OER performance (259 mA/㎠ at 2.4 V) in alkaline solution, although the activities (211 mA/㎠ at 0.5 V) for ORR were not changed with the content of excess Ni. La(CoNi)O3 with excess Ni showed very stable cyclability and low capacity fading rate (0.38 & 0.07 ㎶/hour for ORR & OER) until 300 hours (~70 cycles) but more excess content of Ni in La(CoNi)O3 gave negative effect to cyclability.

• Journal of the Korean Ceramic Society
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• v.45 no.12
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• pp.796-801
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• 2008

$LaGaO_3$ thin film was prepared on Ni-Fe metal porous substrate by Pulsed Laser Deposition method. By the thermal reduction, the dense $NiO-{Fe_3}{O_4}$ substrate is changed to a porous Ni-Fe metal substrate. The volumetric shrinkage and porosity of the substrate are controlled by the reduction temperature. It was found that a thermal expansion property of the Ni-Fe porous metal substrate is almost the same with that of $LaGaO_3$ based oxide. $LaGaO_3$ based electrolyte films are prepared by the pulsed laser deposition (PLD) method. The film composition is sensitively affected by the deposition temperature. The obtained film is amorphous state after deposition. After post annealing at 1073K in air, the single phase of $LaGaO_3$ perovskite was obtained. Since the thermal expansion coefficient of the film is almost the same with that of LSGM film, the obtained metal support LSGM film cell shows the high tolerance against a thermal shock and after 6 min startup from room temperature, the cell shows the almost theoretical open circuit potential.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1998.10b
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• pp.7-7
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• 1998

Research activities of Russian Medical Engineering Center and Institute of Medical Materials of Shape Memory Alloys and Implants are presented as follows: ${\bullet}$ The direction of elaboration of porous shape memory alloys for medicine. ${\bullet}$ Medical and technical requirements and physical and mechanical criteria of porous shape memory implants elaboration. ${\bullet}$ Basic laws of heat-, stress- and strain-induced changes of mechanical properties, shape memory effect and superelasticity in porous TiNi-based alloys. ${\bullet}$ Methods of regulation of shape memory effect parameters in porous alloys and methods for controlling the regulation-induced changes of physical and mechanical properties. ${\bullet}$ Original technologies of elaboration of porous alloys In various fields of medicine. ${\bullet}$ Arrangement of serial production of shape memory porous implants and examples of their medical use.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.231-231
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• 2009

In this work, we prepared the Ni-loaded porous SBA-15 (SBA-15) by a depositionprecipitation (D-P) method, in order to enhance the hydrogen storage capacity. The structure and morphology of the Ni/SBA-15 were characterized by X-ray diffraction (XRD) and field emission transmission electron microscopy (FE-TEM). The results showed that, at the Ni loading used at the DP times in the range of 0-120 min, SBA-15 preserved the well-ordered hexagonal porous arrangement. The textural properties of the Ni/SBA-15 were analyzed using N2 adsorption isotherms at 77 K. Specific surface area and mesopore volume of the samples were determined from the Brunauer-Emmett-Teller (BET) equation and Barrett-Joiner-Halenda (BJH) method, respectively. The hydrogen storage capacity of the Ni/SBA-15 was evaluated at 298 K/10 MPa. The hydrogen storage capacity of the Ni/SBA-15 was increased in accordance with Ni content. Consequently, it was found that the presence of Ni on mesoporous SBA-15 created hydrogen-favorable sites which enhanced the hydrogen storage capacity by spillover effect.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.407.1-407.1
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• 2016

Electrochromism is defined as a phenomenon which involves persistently repeated change of optical properties between bleached state and colored state by simultaneous injection of electrons and ions, sufficient to induce an electrochemical redox process. Due to this feature, considerable progress has been made in the synthesis of electrochromic (EC) materials, improvements of EC properties in EC devices such as light shutter, smart window and variable reflectance mirrors etc. Among the variable EC materials, solid-state inorganics in particular, metal oxide semiconducting materials such as nickel oxide (NiO) have been investigated extensively. The NiO that is an anodic EC material is of special interest because of high color contrast ratio, large dynamic range and low material cost. The high performance EC devices should present the use of standard industrial production techniques to produce films with high coloration efficiency, rapid switching speed and robust reversibility. Generally, the color contrast and the optical switching speed increase drastically if high surface area is used. The structure of porous thin film provides a specific surface area and can facilitate a very short response time of the reaction between the surface and ions. The large variety of methods has been used to prepare the porous NiO thin films such as sol-gel process, chemical bath deposition and sputtering. Few studies have been reported on NiO thin films made by using sol-gel method. However, compared with dry process, wet processes that have the questions of the durability and the vestige of bleached state color limit the thin films practical use, especially when prepared by sol-gel method. In this study, we synthesis the porous NiO thin films on the fluorine doped tin oxide (FTO) glass by using sputtering and anodizing method. Also we compared electrical and optical properties of NiO thin films prepared by sol gel. The porous structure is promised to be helpful to the properties enhancement of the EC devices.

• Journal of Powder Materials
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• v.15 no.4
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• pp.308-313
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• 2008

Al-Ni alloy nano powders have been produced by the electrical explosion of Ni-plated Al wire. The porous nano particles were prepared by leaching for Al-Ni alloy nano powders in 20wt% NaOH aqueous solution. The structural properties of leached porous nano powder were investigated by nitrogen physisorption, X-ray diffraction (XRD) and transmission Microscope (TEM). The surface areas of the leached powders were increased with amounts of AI in alloys. The pore size distributions of these powders were exhibited maxima at range of pore diameters 3.0 to 3.5 nm from the desorption isotherm. The maximum values of those were decreased with amounts of Al in alloys.

• Journal of the Korean institute of surface engineering
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• v.37 no.5
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• pp.289-295
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• 2004

A dense palladium-nikel (Pd-Ni) alloy composite membrane has been fabricated on microporous nickel support mixed with submicron/micron nickel powder instead of mesoporous stainless steel support. Plasma treatment process is introduced as pre-treatment process instead of HCI activation. Pd-Ni alloy composite membrane prepared by electro plating was fairly a uniform and dense surface morphology. The membrane was characterized by permeation experiments with hydrogen and nitrogen gases at temperature 773 K and pressure 2.2 psi. The results showed that hydrogen ($H_2$) permeance was 27 ml/$\textrm{cm}^2$ㆍatmㆍmin and hydrogen/ nitrogen ($_H2$$N_2$) selectivity was 8 at 773 K.