Steam reforming of liquefied natural gas (LNG) for hydrogen production over nickel–boron–alumina xerogel catalyst

Park, Seungwon,Yoo, Jaekyeong,Han, Seung Ju,Song, Ji Hwan,Lee, Eo Jin,Song, In Kyu Pergamon Press 2017 International journal of hydrogen energy Vol.42 No.22

<P><B>Abstract</B></P> <P>A series of mesoporous nickel–boron–alumina xerogel (<I>x</I>-NBA) catalysts with different boron/nickel molar ratio (<I>x</I> = 0–1) were prepared by an epoxide-driven sol–gel method. The effect of boron/nickel molar ratio on the catalytic activities and physicochemical properties of nickel–boron–alumina xerogel catalysts was investigated in the steam reforming of liquefied natural gas (LNG). All the mesoporous <I>x</I>-NBA catalysts showed similar surface area. Introduction of boron increased interaction between nickel and support. In addition, introduction of boron into <I>x</I>-NBA catalysts reduced methane activation energy and increased nickel surface area. Promotion of boron had a positive effect on the catalytic activity due to the increase of adsorbed methane and nickel surface area. The amount of adsorbed methane and nickel surface area exhibited volcano-shaped trends with respect to boron/nickel molar ratio. LNG conversion and hydrogen yield increased with increasing the amount of adsorbed methane and with increasing nickel surface area. Among the catalysts, 0.3-NBA, which retained the largest amount of adsorbed methane and the highest nickel surface area, showed the best catalytic performance. It was also revealed that <I>x</I>-NBA catalysts showed strong coke resistance during the steam reforming reaction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ni–B–Al<SUB>2</SUB>O<SUB>3</SUB> (<I>x</I>-NBA) catalysts with different B/Ni molar ratio (<I>x</I> = 0–1) were prepared. </LI> <LI> Hydrogen was produced by steam reforming of liquefied natural gas (LNG). </LI> <LI> Hydrogen yield increased with increasing the amount of adsorbed methane. </LI> <LI> Hydrogen yield increased with increasing nickel surface area. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effect of Ni/Al atomic ratio of mesoporous Ni–Al₂O₃ aerogel catalysts on their catalytic activity for hydrogen production by steam reforming of liquefied natural gas (LNG)

Seo, Jeong Gil,Youn, Min Hye,Bang, Yongju,Song, In Kyu Elsevier 2010 International journal of hydrogen energy Vol.35 No.22

<P><B>Abstract</B></P><P>Mesoporous Ni–Al<SUB>2</SUB>O<SUB>3</SUB> (<I>X</I>NiAE) aerogel catalysts with different Ni/Al atomic ratio (<I>X</I>) were prepared by a single-step sol-gel method and a subsequent CO<SUB>2</SUB> supercritical drying method. The effect of Ni/Al atomic ratio of mesoporous <I>X</I>NiAE aerogel catalysts on their physicochemical properties and catalytic activity for steam reforming of liquefied natural gas (LNG) was investigated. Textural properties and chemical properties of <I>X</I>NiAE catalysts were strongly influenced by Ni/Al atomic ratio. Nickel species were highly dispersed on the surface of <I>X</I>NiAE catalysts through the formation of surface nickel aluminate phase. In the steam reforming of LNG, both LNG conversion and hydrogen yield showed volcano-shaped curves with respect to Ni/Al atomic ratio. Average nickel diameter of <I>X</I>NiAl catalysts was well correlated with LNG conversion and hydrogen yield over the catalysts. Among the catalysts tested, 0.35NiAE (Ni/Al=0.35) catalyst with the smallest average nickel diameter showed the best catalytic performance. The highest surface area, the largest pore volume, the largest average pore size, and the highest reducibility of 0.35NiAE catalyst were also partly responsible for its superior catalytic performance.</P> <P><B>Research highlights</B></P><P>►Hydrogen was produced by steam reforming of liquefied natural gas (LNG). ►Mesoporous Ni–Al<SUB>2</SUB>O<SUB>3</SUB> aerogel catalysts were used. ►Catalytic performance strongly depended on Ni/Al atomic ratio. ►Average nickel diameter played an important role.</P>

Mill Scale for Synthesis of Fe–Ni and Fe–Ni–Co Alloys through Gaseous Reduction: Reaction Kinetics and Mechanism

Bahgat, M.,Paek, Min-Kyu,Pak, Jong-Jin The Iron and Steel Institute of Japan 2008 ISIJ international Vol.48 No.11

<P>Nickel and Nickel cobalt ferrite powders were prepared through the ceramic route by calcination of a stoichiometric mixture of nickel oxide, cobalt oxide and mill scale as source for iron oxide. The produced ferrites powders were isothermally reduced in pure hydrogen at 800–1100°C. Based on thermogravimetric analysis, the reduction behavior of the synthesized ferrite and the kinetics reaction mechanism were studied. The initial ferrite powder and the various reduction products were characterized by XRD, SEM and reflected light microscope to reveal the effect of hydrogen reduction on composition, microstructure and reaction kinetics of synthesized ferro-alloys. The activation energy values were calculated from Arrhenius equation. The approved mathematical formulations for the gas solid reaction were applied to confirm the estimated rate controlling reaction mechanism. Complete reduction of home made ferrite powder was achieved with synthesize of nanocrystalline Fe–Ni and Fe–Ni–Co alloys.</P>

Effect of silver addition on the properties of nickel–titanium alloys for dental application

Oh, Keun-Taek,Joo, Uk-Hyon,Park, Gee-Ho,Hwang, Chung-Ju,Kim, Kyoung-Nam Wiley Subscription Services, Inc., A Wiley Company 2006 Journal of Biomedical Materials Research Part B Vol. No.

<P>Equiatomic and near-equiatomic nickel–titanium alloys exhibit a shape-memory effect and superelasticity. However, the properties of such alloys are extremely sensitive to the precise nickel–titanium ratio and the addition of alloying elements. High corrosion resistance is necessary for biomedical applications, especially orthodontic. The purpose of this study was to investigate the effect of silver addition to nickel–titanium alloys for dental and medical application. Arc melting, homogenization, hot rolling, and solution heat treatment were performed to prepare the nickel–titanium–silver (NiTi-Ag) specimens. The properties of the ternary NiTi–Ag alloys such as phase-transformation temperature, microstructure, microhardness, corrosion resistance, and cytotoxicity were investigated. The NiTi-Ag alloys showed low silver recovery rate for the cast alloy, due to silver's low evaporation temperature, and low silver solubility in nickel–titanium. Silver addition to nickel–titanium increased the transition temperature range to 100°C and stabilized the martensitic phase (monoclinic structure) at room temperature, because the martensitic transformation starting temperature (M<SUB>s</SUB>) was above room temperature. Martensitic and austenitic phases existed in X-ray diffraction patterns of solution-annealed NiTi-Ag alloys. The silver addition was considered to improve the corrosion resistance and form a stable passive film. Significantly, the mechanical properties of the silver-added alloys were dependent upon the amount of alloying addition. There was no toxicity in the NiTi-Ag alloys, as the response index showed none or mild levels. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006</P>

The geometric effect of an off-centered cross-section on nickel–titanium rotary instruments: A finite element analysis study

Ha, Jung-Hong,Kwak, Sang Won,Versluis, Antheunis,Lee, Chan-Joo,Park, Se-Hee,Kim, Hyeon-Cheol Association for Dental Sciences of the Republic of 2017 Journal of Dental Sciences Vol.12 No.2

<P><B>Background/purpose</B></P><P>Geometric design dictates the mechanical performance of nickel–titanium rotary instruments. Using finite element (FE) analysis, this study evaluated the effects of an off-centered cross-sectional design on the stiffness and stress distribution of nickel–titanium rotary instruments.</P><P><B>Materials and methods</B></P><P>We constructed three-dimensional FE models, using ProTaper-NEXT type design (PTN) as well as three other virtual instruments with varied cross-sectional aspect ratios but all with the same cross-sectional area. The cross-sectional aspect ratio of the PTN was 0.75, while others were assigned to have ratios of 1.0 (square), 1.5 (rectangle), and 2.215 (centered-rectangle). The PTN center of the cross-section was ‘<I>k</I>’, while others were designed to have 0.9992<I>k</I>, 0.7<I>k</I>, and 0 for the square, rectangle, and centered-rectangle models, respectively. To compare the stiffness of the four FE models, we numerically analyzed their mechanical response under bending and torque.</P><P><B>Results</B></P><P>Under the bending condition, the square model was found to be the stiffest, followed by the PTN, rectangle, and then the centered-rectangle model. Under the torsion, the square model had the smallest distortion angle, while the rectangular model had the highest distortion angle.</P><P><B>Conclusion</B></P><P>Under the limitation of this study, the PTN type off-centered cross-sectional design appeared the most optimal configuration among the tested designs for high bending stiffness with cutting efficiency while rotational stiffness remained similar with the other designs.</P>

Nickel–copper hybrid electrodes self-adhered onto a silicon wafer by supersonic cold-spray

Lee, Jong-Gun,Kim, Do-Yeon,Kang, Byungjun,Kim, Donghwan,Song, Hee-eun,Kim, Jooyoung,Jung, Woonsuk,Lee, Dukhaeng,Al-Deyab, Salem S.,James, Scott C.,Yoon, Sam S. Elsevier 2015 Acta materialia Vol.93 No.-

<P><B>Abstract</B></P> <P>High-performance electrodes are fabricated through supersonic spraying of nickel and copper particles. These electrodes yield low specific resistivities, comparable to electrodes produced by screen-printed silver paste and light-induced plating. The appeal of this fabrication method is the low cost of copper and large area scalability of supersonic spray-coating techniques. The copper and nickel electrode was fabricated in the open air without any pre- or post-treatment. The spray-coated copper–nickel electrode was characterized by optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, and energy dispersive spectroscopy. Although both SEM and TEM images confirmed voids trapped between flattened particles in the fabricated electrode, this electrode’s resistivity was order 10<SUP>−6</SUP> Ωcm, which is comparable to the bulk value for pure copper.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

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

Kim, Chang-Duk,Truong, Nguyen Tam Nguyen,Pham, Viet Thanh Hau,Jo, Younjung,Lee, Hyeong-Rag,Park, Chinho Elsevier 2019 Materials chemistry and physics Vol.223 No.-

<P><B>Abstract</B></P> <P>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 H<SUB>2</SUB>. 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<SUP>−3</SUP> 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.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ni–graphite core shell nanoparticles (CSNPs) are prepared at different temperatures. </LI> <LI> NiO NPs are reduced with H<SUB>2</SUB> gas to generate Ni NPs. </LI> <LI> The chemical reactions for the formation of Ni NPs are proposed. </LI> <LI> The resistivity of the electrode pattern of Ni-graphite CSNPs is 6.75 × 10<SUP>−3</SUP> Ω cm. </LI> <LI> Solar cells with Ni-graphite CSNPs show better power conversion efficiency (3.3%). </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A Pd–Cu–Ni Ternary Alloyed Membrane on Porous Nickel Support Prepared by Sputtering and Copper Reflow

Kim, Dong-Won,Um, Ki-Youn,Kim, Heung-Gu,Lee, In-Seon,Kim, Sang-Ho,Park, Jong-Soo,Ryi, Shin-Kun,Cho, Sung-Ho The Japan Society of Applied Physics 2005 Japanese journal of applied physics Vol.44 No.1

<P>We propose a ternary, Pd–Cu–Ni, alloyed membrane on porous nickel support that dramatically enhances the hydrogen selectivity by using sputtering and copper reflow. Porous nickel support made by sintering shows strong resistance to hydrogen embrittlement and thermal fatigue. To improve the hydrogen selectivity of the membrane, fabricated the layer sequence of Cu/Pd/Ni on porous nickel support replaced that of conventional Pd/Cu/Ni and then reflow was performed at 700°C. Consequently, copper was reflowed unilaterally into Pd/Ni layer, thereby avoiding delamination by the interlayered copper and enabling infinite hydrogen selectivity because of extremely dense coatings.</P>

Preparation and characterization of sulfonated poly(phenylene)s membranes containing conjugated moiety via nickel catalyzed carbon–carbon coupling polymerization

Jang, Hohyoun,Hong, Taehoon,Yoo, Jiho,Lee, Soonho,Pyo, Jaeseung,Sutradhar, Sabuj Chandra,Ju, Hyunchul,Kim, Whangi Elsevier 2015 International journal of hydrogen energy Vol.40 No.41

<P><B>Abstract</B></P> <P>A series of sulfonated polyphenylene membranes (SPBCDPEs) containing conjugated tetraphenylethylene moieties were synthesized via Ni(0) catalyzed polymerization, and subsequent sulfonation with concentrated sulfuric acid. These membranes showed improved performance in ion exchange capacity, water uptake, proton conductivity, and thermal stability over Nafion 211<SUP>®</SUP> membranes. The membranes' thermal properties were investigated by thermo-gravimetric analysis (TGA) and also surface morphologies were assessed by atomic force microscope (AFM). SPBCDPEs may have applications as fuel cell membranes due to excellent proton conductivity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We synthesized sulfonated polyphenylene containing conjugated structure. </LI> <LI> We controlled the degree of sulfonation by BCDPE monomer. </LI> <LI> Increasing sulfonation level increases proton conductivity. </LI> <LI> Membranes showed good performance with high proton conductivity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Sulfonated carbon–carbon structured copolymers (SPBCDPEs) are described: A series of sulfonated polyphenylene membranes (SPBCDPEs) containing conjugated tetraphenylethylene moieties were synthesized via Ni(0) catalyzed polymerization, and subsequent sulfonation with concentrated sulfuric acid. The proposed polymer membranes, without ether linkages, demonstrated good chemical stability, proton conductivity, and solubility in aprotic organic solvents.</P> <P>[DISPLAY OMISSION]</P>

<i>In situ</i> growth of hierarchical mesoporous NiCo₂S₄@MnO₂ arrays on nickel foam for high-performance supercapacitors

Nguyen, Van Hoa,Shim, Jae-Jin Elsevier 2015 ELECTROCHIMICA ACTA Vol.166 No.-

<P><B>Abstract</B></P> <P>Hierarchical mesoporous NiCo<SUB>2</SUB>S<SUB>4</SUB>@MnO<SUB>2</SUB> core–shell structured arrays on nickel foam were designed and fabricated using a facile hydrothermal method for supercapacitor applications. The electrodes exhibited rapid electron and ion transport, large electroactive surface area, and excellent structural stability owing to the highly conducting nature of the well-defined mesoporous NiCo<SUB>2</SUB>S<SUB>4</SUB> nanowire arrays in combination with the large surface area provided by the ultrathin MnO<SUB>2</SUB> nanosheets and ultralong MnO<SUB>2</SUB> nanowires, as well as to the open framework of the three-dimensional nanoarchitectures. The specific capacitance of the resulting electrode was as high as 17.5Fcm<SUP>−2</SUP> at a very high current density of 100mAcm<SUP>−2</SUP>, highlighting its potential as an efficient electrode for electrochemical capacitors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mesoporous NiCo<SUB>2</SUB>S<SUB>4</SUB>@MnO<SUB>2</SUB> arrays have been decorated on Ni foam. </LI> <LI> The electrode exhibits a high specific capacitance of 17.5Fcm<SUP>−2</SUP> at 100mAcm<SUP>−2</SUP>. </LI> <LI> The electrode presents rapid electron transport and large electroactive surface area. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>