Promotional effect of Ga for Ni₂P catalyst on hydrodesulfurization of 4,6-DMDBT

Jang, Jung-Geun,Lee, Yong-Kul Elsevier 2019 Applied Catalysis B Vol.250 No.-

<P><B>Abstract</B></P> <P>Ni<SUB>2</SUB>P catalysts supported on SiO<SUB>2</SUB> and Ga-SiO<SUB>2</SUB> were prepared by incipient wetness impregnation technique, and the effect of the electronic properties of Ni<SUB>2</SUB>P on hydrodesulfurization (HDS) performance was studied. X-ray diffraction (XRD), X-ray absorption near edge structure (XANES), and in situ FT-IR with CO adsorption studies were used to examine structural and electronic properties of the supported Ni<SUB>2</SUB>P catalysts. The catalytic activity in hydrodesulfurization (HDS) was measured at 3.0 MPa and at three different temperatures of 613, 628, and 643 K in a three-phase fixed bed reactor using a model feed containing 500 ppm S as 4,6-DMDBT, 6000 ppm S as DMDS, 100 ppm N as quinoline, 1 wt% tetralin, and 0.5 wt% n-nonane in n-tridecane balance. In both cases, the HDS conversion was very high over 90%. For the product distributions, the Ni<SUB>2</SUB>P/SiO<SUB>2</SUB> maintained a low direct desulfurization (DDS) selectivity at 26.5%, while the Ni<SUB>2</SUB>P/Ga-SiO<SUB>2</SUB> exhibited higher DDS selectivity of 32.1% at 643 K. The Ni K-edge XANES and CO-adsorbed FT-IR analysis confirmed the electron enriched property of Ni<SUB>2</SUB>P on SiO<SUB>2</SUB>, but with the electron deficiency of Ni<SUB>2</SUB>P phase supported on Ga-SiO<SUB>2</SUB> support. These results thus suggest that the electron deficient Ni<SUB>2</SUB>P favors σ-bonding with S compounds to promote direct desulfurization of 4.6-DMDBT.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ni<SUB>2</SUB>P/Ga-SiO<SUB>2</SUB> shows a higher DDS selectivity than Ni<SUB>2</SUB>P/SiO<SUB>2</SUB> in the HDS of 4,6-DMDBT. </LI> <LI> The Ga addition induces electron-deficient Ni<SUB>2</SUB>P favoring σ-bonding with 4,6-DMDBT. </LI> <LI> The high DDS selectivity of Ni<SUB>2</SUB>P/Ga-SiO<SUB>2</SUB> allows less H<SUB>2</SUB> consumption in the HDS. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Ultrasonic synthesis, characterization and energy applications of Ni–B alloy nanorods

Edison, Thomas Nesakumar Jebakumar Immanuel,Atchudan, Raji,Karthik, Namachivayam,Sethuraman, Mathur Gopalakrishnan,Lee, Yong Rok Elsevier 2017 Journal of the Taiwan Institute of Chemical Engine Vol.80 No.-

<P><B>Abstract</B></P> <P>Alloy nanostructures had received much attention for their applications in energy, catalysis, and optics. This paper described a facile ultrasonic approach for the synthesis of Ni–B alloy nanorods (Ni–B NRs). The crystallinity, chemical state, surface area and surface morphology of Ni–B NRs were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N<SUB>2</SUB> adsorption–desorption isotherms and high-resolution transmission electron microscopy (HR–TEM) analyses, respectively. The electrocatalytic behavior of Ni–B NRs toward the oxygen evolution reaction (OER) was studied by linear sweep voltammetry (LSV) and Tafel polarization methods in 0.1 M aqueous KOH. The LSV results of Ni–B NRs showed very low OER onset potential of 1.44 V<SUB>RHE</SUB> with an overpotential of 212 mV<SUB>RHE</SUB>. The Ni–B NRs attained 10 mA/cm<SUP>2</SUP> of current density at a very low potential of 1.61 V<SUB>RHE</SUB> than bare SS (1.87 V<SUB>RHE</SUB>) and bare Pt (2.50 V<SUB>RHE</SUB>). Further, Ni–B NRs showed a low Tafel slope of 45 mV/dec when compared to other standard materials, revealed the fast OER kinetics. The calculated specific capacitance of synthesized Ni–B NRs was 581 F/g, from the results of cyclic voltammetry at a scan rate of 2 mV/s. The electrocatalytic and supercapacitor studies exposed that the synthesized Ni–B NRs can be used as an electrocatalyst for OER as well as pseudocapacitor for commercial electric vehicles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Amorphous Ni–B alloy nanorods (Ni–B NRs) are synthesized by ultrasonic method. </LI> <LI> Ni–B NRs shows excellent electrocatalytic activity toward OER than Ru and Ir. </LI> <LI> Ni–B NRs exhibit good pseudocapacitor behavior in aqueous KOH. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Glycine nitrate process에 의한 제조된 SOFC anode용 Ni-YSZ cermet의 물성

이태석,고정훈,이강식,김복희,Lee, Tae-Suk,Ko, Jung-Hoon,Lee, Kang-Sik,Kim, Bok-Hee 한국결정성장학회 2011 韓國結晶成長學會誌 Vol.21 No.1

Ni-YSZ(Yttria Stabilized Zirconia) composite powders를 glycine nitrate process으로 만들었다. 합성된 분말은 $1300{\sim}1400^{\circ}C$ 4시간 동안 소성하였으며 $1000^{\circ}C$에서 2시간 동안 질소 및 수소 분위기에서 환원 소성하여 Ni-YSZ cermet을 제조하였다. Ni의 부피비를 변화 시켜 각기 그들의 미세구조, 전기전도도, 열팽창 및 강도 특성을 알아보았다. Ni과 YSZ 상 사이에 상호 연결된 균질하게 분포된 다공성 미세구조를 얻을 수 있었다. 기공률, 전기전도도, 열팽창계수 및 곡강도 모두 Ni의 양에 민감하게 영향 받는 것을 알 수 있으며 40 vol%의 Ni를 함유한 Ni-YSZ cermet가 전극재료로 가장 적당하였다. $1350^{\circ}C$에서 소성한 40 vol% Ni-YSZ 시편의 경우 30 %의 기공율, 65.5 Mpa의 강도, 917.4 S/cm의 전기 전도도($1000^{\circ}C$)및 $12.6{\times}10^{-6}^{\circ}C^{-1}$의 열팽창계수($1000^{\circ}C$)를 가져 YSZ 전해질의 음극재료로 가장 적합하였다. Ni-YSZ (Yttria Stabilized Zirconia) composite powders were fabricated by glycine nitrate process. The prepared powders were sintered at $1300{\sim}1400^{\circ}C$ for 4 h in air and reduced at $1000^{\circ}C$ for 2 h in a nitrogen and hydrogen atmosphere. The microstructure, electrical conductivity, thermal expansion and mechanical properties of the Ni-YSZ cermets have been investigated with respect to the volume contents of Ni. A porous microstructure consisting of homogeneously distributed Ni and YSZ phases together with well-connected grains was observed. It was found that the open porosity, electrical conductivity, thermal expansion and bending strength of the cermets are sensitive to the volume content of Ni. The Ni-YSZ cermet containing 40 vol% Ni was ascertained to be the optimum composition. This composition offers sufficient open porosity of more than 30 %, superior electrical conductivities of 917.4 S/cm at $1000^{\circ}C$ and a moderate average thermal expansion coefficient of $12.6{\times}10^{-6}^{\circ}C^{-1}$ between room temperature and $1000^{\circ}C$.

Influence of Phosphorous Content on Microstructure Development at the Ni-P Plating/SAC Interface

Zbigniew Huber,Joanna Wojewoda-Budka,Anna Wierzbicka-Miernik,Anna Sypien,Maciej Szczerba,Pawel Zieba 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.1

Studies of the commonly used Ni-P surface finish of 4.3 and 11.6 wt. %of P content electroless plated on nickel substrates followed by theirreaction with SAC305 solder were performed. It was demonstratedthat the Ni-4.3P plating was crystalline, while the Ni-11.6P wasmostly amorphous. The transformation of the Ni-P into Ni3P phasetook place at 672 K and 605 K for low and high P amount, respectively. The activation energy (Ea) of the crystallization processes in the Ni-Pplating was lower for the Ni-11.6P plating. Interaction of SAC305solder with both types of the inspected plating showed the creation of(Cu,Ni)6Sn5 phase in the form of thin layer and large scallops, whilefor Ni-11.6P/SAC305 interface also (Ni,Cu)3Sn4 phase. The thicknessof these phases was larger in the case of low phosphorous containingplating. The Ni-11.6P plating after the reaction with SAC305 totallytransformed into Ni12P5, while the enrichment in P up to 10.5 wt. %occurred in the Ni-4.3P which did not lead to the appearance of anyNixPy type phases. After the reaction of plating with solder the Ni2SnPphase was not identified. This was related to the absence of spallingphenomenon of the intermetallics into solder.

Ni-Fe-Ti 기계적 합금의 구조 및 자기적 특성

양동석,판더롱,유성초 한국물리학회 2016 새물리 Vol.66 No.7

In this work, we produced Ni$_{40}$Fe$_{20}$Ti$_{40}$ mechanical alloys by using a mechanical milling system. In the alloying process, mixed powders of Ni, Fe and Ti with the same concentration were milled sequentially by using zirconia balls for 1, 2, 4, and 12 hours in a container filled with Ar gas. The saturated magnetizations of the samples were measured by using a vibrating sample magnetometor (VSM). From the measurement, we found that the saturated magnetizations of Ni$_{40}$Fe$_{20}$Ti$_{40}$ milled for 2$\sim$12 hours were similar to those of Ni$_{60}$Ti$_{40}$ alloys milled for the same periods. The structures of the samples were examined by using an extended X-ray absorption fine structure (EXAFS) analysis. From the structural analysis, we found that the long-range order of the Ni atoms in a Ni$_{40}$Fe$_{20}$Ti$_{40}$ mixed powder disappeared rapidly during process of mechanical alloying, but the local structures around the Fe atoms in the mixed powder changed gradually and the basic shells of the body-centered cubic (BCC) structure of Fe remained even for long durations of the alloying process. 본 연구에서 기계적 분말 장치를 이용하여 Ni$_{40}$Fe$_{20}$Ti$_{40}$ 기계적 합금을 제조하였다. 이 합금화 과정에서 Ni$_{40}$Fe$_{20}$Ti$_{40}$와 같은 조성의 Ni, Fe, Ti의 혼합 분말들은 Ar 기체가 채워진 용기 내에서 지르코니아 볼에 의해 연속적으로 밀링되었다. 시료의 포화 자화는 진동 시료 자력계 (VSM)로 측정되었으며, 측정결과 2$\sim$12시간 동안 밀링한 Ni$_{40}$Fe$_{20}$Ti$_{40}$ m합금의 포화 자화 값들이 같은 시간 동안 밀링한 Ni$_{60}$Ti$_{40}$ 합금의 자화 값과 비슷한 것을 발견하였다. 시료의 구조는 미세구조분석 (EXAFS)에 의해 되었고, 이 분석으로부터 초기에 Ni$_{40}$Fe$_{20}$Ti$_{40}$ 혼합 분말 시료에 있던 Ni 원자들의 장거리 질서도가 빨리 사라지는 반면 Fe 원자들의 장거리 질서도는 점진적으로 변하여 철의 BCC 구조의 기본단위체의 특징이 오래남아 있고 합금화 과정의 오랜 시간동안 지속되는 것을 발견하였다.

Direct observation of interfacial reaction of Ni/6H-SiC and carbon redistribution by in situ transmission electron microscopy

Kwon, Yena,An, Byeong-Seon,Yang, Cheol-Woong Elsevier 2018 Materials characterization Vol.140 No.-

<P><B>Abstract</B></P> <P>The interfacial reaction of Ni/SiC has been attracting considerable attention because SiC substrate has excellent chemical and thermal stability and low electrical resistivity, which are essential properties for various device applications. However, research on the initial reaction at low temperature and exact mechanism is currently insufficient. Therefore, we investigated the reaction of Ni films on a 6H-SiC substrate and the behavior of carbon at 550 °C by direct observation with transmission electron microscopy (TEM) during in situ heating. At 550 °C, the Ni<SUB>31</SUB>Si<SUB>12</SUB> phase formed during the reaction of Ni and SiC. The Ni silicide layer thickened as the reaction front proceeded toward the 6H-SiC substrate and carbon atoms from decomposed SiC converted into graphite. In addition, carbon existed in three regions. First, carbon existed as graphite on the external surface of Ni silicide layer during initial reaction. Second, graphite formed at the original interface between the Ni film and the 6H-SiC substrate. Finally, carbon existed at the bottom of the Ni silicide region due to its low diffusivity in the silicide. The elemental distribution of Ni, Si, and C was observed in detail through various analytical techniques. We demonstrate the reaction mechanism of Ni and SiC at 550 °C and the distribution of carbon atoms.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Interfacial reaction mechanism for Ni/SiC at 550 °C is investigated in situ by TEM. </LI> <LI> NBED, EDS and EELS analyses were performed to identify the phases formed. </LI> <LI> Carbon atoms from decomposed SiC were redistributed in three different regions. </LI> <LI> Graphite/Ni<SUB>31</SUB>Si<SUB>12</SUB>/Ni<SUB>31</SUB>Si<SUB>12</SUB> + graphite/6H-SiC structure was observed after the reaction. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

Ni/SIRAL-30 as a heterogeneous catalyst for ethylene oligomerization

Lee, Maeum,Yoon, Ji Woong,Kim, Youngmin,Yoon, Ji Sun,Chae, Ho-Jeong,Han, Yo-Han,Hwang, Dong Won Elsevier 2018 Applied catalysis. A, General Vol.562 No.-

<P><B>Abstract</B></P> <P>The oligomerization of ethylene is an important catalytic process for the production of higher olefins, and is also a key step for jet-fuel production from bioethanol. We herein investigated the use of Ni/SIRAL-30 as a heterogeneous catalyst for ethylene oligomerization, as it can be prepared easily and cheaply by the simple impregnation of a Ni precursor on a commercial SIRAL-30 support with a high Brønsted acid site (BAS) density. Pyridine-infrared spectroscopy confirmed that proton species in the bridge-type Si-OH-Al frameworks of SIRAL-30 were partially exchanged with Ni<SUP>2+</SUP> cations without interfering with the Al<SUP>3+</SUP> sites. In addition, the Ni species following catalyst calcination under air and pretreatment with N<SUB>2</SUB> was identified to be the isolated Ni<SUP>2+</SUP> by XPS, EXAFS and CO adsorption. The Ni/SIRAL-30 catalyst gave almost complete ethylene conversion and stability over 100 h at 200 °C, 10 bar pressure, and at a weight hourly space velocity of 0.375 h<SUP>−1</SUP> during continuous ethylene oligomerization. A Ni loading of 4 wt% on SIRAL-30 was optimal for both ethylene conversion and for maximizing the proportion of C<SUB>10+</SUB> products formed, while the pretreatment of Ni(4 wt%)/SIRAL-30 at 550 °C under N<SUB>2</SUB> resulted in the best catalytic activity. Although a degree of deactivation was observed due to the adsorption of heavy oligomers, the initial catalytic activity was restored by heating the used catalyst at 550 °C under air. These results confirm that the Ni(4 wt%)/SIRAL-30 catalyst is both recyclable and an efficient heterogeneous catalyst for continuous ethylene oligomerization.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ni/SIRAL-30 was investigated as a heterogeneous catalyst for ethylene oligomerization. </LI> <LI> N<SUB>2</SUB> pretreatment of Ni/SIRAL-30 enhanced Ni<SUP>2+</SUP> dispersion and Brønsted acid site density. </LI> <LI> 4 wt% Ni loading on SIRAL-30 was optimal for both ethylene conversion and C<SUB>10+</SUB> products. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Morphology effect of β-zeolite supports for Ni₂P catalysts on the hydrocracking of polycyclic aromatic hydrocarbons to benzene, toluene, and xylene

Kim, Yong-Su,Cho, Kye-Sung,Lee, Yong-Kul Elsevier 2017 Journal of catalysis Vol.351 No.-

<P><B>Abstract</B></P> <P>Ni<SUB>2</SUB>P catalysts supported on nano-sized β (β-N) or micrometer-sized β (β-M) zeolites were prepared by temperature-programmed reduction, and their structural and chemical properties were analyzed by N<SUB>2</SUB> physisorption, transmission electron microscopy, X-ray diffraction, extended X-ray absorption fine structure, NH<SUB>3</SUB> temperature-programmed desorption, and CO uptake. The catalytic activity was tested at 653K and 6.0MPa in a fixed bed reactor for the hydrocracking of 1-methylnaphthalene (1-MN) into benzene, toluene, and xylene (BTX). In the hydrocracking, Ni<SUB>2</SUB>P/β-N showed better activity and stability for hydrocracking of 1-MN than Ni<SUB>2</SUB>P/β-M, with BTX yields of 42.3% and 30.5% for Ni<SUB>2</SUB>P/β-N and Ni<SUB>2</SUB>P/β-M, respectively. In addition, Ni<SUB>2</SUB>P/β-N maintained the stability in terms of catalytic activity and local structure, while Ni<SUB>2</SUB>P/β-M suffered from coke formation, particularly in the presence of heavy aromatics such as phenanthrene in the feed. The characterization results demonstrated that the β-N has abundant intercrystalline mesopores to provide better dispersion for Ni<SUB>2</SUB>P catalysts and accessibility toward acid sites, offering the proximity of the hydrogenation active center and the cracking sites. Kinetic analysis for the hydrocracking of 1-MN over the catalysts revealed that the Ni<SUB>2</SUB>P/β-N catalyst shows superior activity for both hydrogenation and cracking over the Ni<SUB>2</SUB>P/β-M catalyst.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ni<SUB>2</SUB>P/β catalysts are active in 1-methylnaphthalene (1-MN) hydrocracking (HCK) to produce benzene, toluene, and xylene (BTX). </LI> <LI> Ni<SUB>2</SUB>P/β-N catalyst promotes 1-MN HCK with BTX yield over 42%. </LI> <LI> Interparticulate mesopore system of β-N offers high dispersion of Ni<SUB>2</SUB>P particles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

63Ni 밀봉선원용 Ni 전기도금 박막에서 Ni 농도가 잔류응력에 미치는 영향

윤필근(Pilgeun Yoon),박덕용(Deok-Yong Park) 한국표면공학회 2017 한국표면공학회지 Vol.50 No.1

Chloride plating solution was fabricated by dissolving metal Ni powders in a mixed solution with HCl and de-ionized water. Effects of Ni2+ and saccharin concentrations in the plating baths on current efficiency, residual stress, surface morphology and microstructure of Ni films were studied. In the case of 0.2 M Ni2+ concentration, current efficiency was decreased to about 65 % with increasing saccharin concentration, but, in the case of 0.7 M Ni2+ concentration, it was shown more than 90 % with the increase of saccharin concentration. Residual stress of Ni thin film was appeared to be about 400 MPa up to 0.0244 M saccharin concentration at the 0.2 M Ni2+ concentration and surface morphology with severe cracks was observed in the range of 0.0487~0.0975 M saccharin concentration. Residual stress of Ni thin films was measured to be about 750 MPa without saccharin addition and 114~148 MPa at the range of 0.0097~0.0975 M saccharin concentration for the 0.7 M Ni2+ concentration. Relatively low residual stress values (114~148 MPa) of the Ni films at the range of 0.0097~0.0975 M saccharin concentration may be resulted from codeposition of S from saccharin. Ni films at 0.7 M Ni2+ concentration showed smooth surface morphology and were independent of saccharin concentration. Ni films at 0.7 M Ni2+ concentration consist of FCC(111), FCC(200), FCC(220) and FCC(311) peaks and the intensities of FCC(111) and FCC(200) peaks increased with increasing saccharin concentration. Also, the average grain size decreased with increasing saccharin concentration from about 30 nm to about 15 nm.

Effects of rapid thermal annealing on structural, magnetic and optical properties of Ni-doped ZnO thin films

Xing Zhao,Erjia Liu,R.V. Ramanujan,Jingsheng Chen 한국물리학회 2012 Current Applied Physics Vol.12 No.3

XPS depth profiles were used to investigate the effects of rapid thermal annealing under varying conditions on the structural, magnetic and optical properties of Ni-doped ZnO thin films. Oxidization of metallic Ni from its metallic state to two-valence oxidation state occurred in the film annealed in air at 600 ℃, while reduction of Ni2+ from its two-valence oxidation state to metallic state occurred in the film annealed in Ar at 600 and 800 ℃. In addition, there appeared to be significant diffusion of Ni from the bottom to the top surface of the film during annealing in Ar at 800 ℃. Both as-deposited and annealed thin films displayed obvious room temperature ferromagnetism (RTFM) which was from metallic Ni, Ni2+or both with two distinct mechanisms. Furthermore, a significant improvement in saturation magnetization (Ms) in the films was observed after annealing in air (Ms= 0.036 mB/Ni) or Ar (Ms= 0.033 mB/Ni) at 600 ℃ compared to that in as-deposited film (Ms = 0.017 mB/Ni). An even higher Ms value was observed in the film annealed in Ar at 800 ℃ (Ms= 0.055 mB/Ni) compared to that at 600 ℃ mainly due to the diffusion of Ni. The ultraviolet emission of the Ni-doped ZnO thin film was restored during annealing in Ar at 800 ℃, which was also attributed to the diffusion of Ni.