• Title, Summary, Keyword: $LaNiO_3$

Search Result 170, Processing Time 0.031 seconds

Preparation of La0.5Nd0.5Ni5 Alloy by an Electrochemical Reduction in Molten LiCl (LiCl 용융염에서 전해환원법을 통한 La0.5Nd0.5Ni5 합금 제조)

  • Lim, Jong Gil;Jeong, Sang Mun
    • Korean Chemical Engineering Research
    • /
    • v.53 no.2
    • /
    • pp.145-149
    • /
    • 2015
  • The electrochemical behavior of $Nd_2O_3-La_2O_3-NiO$ mixed oxide including rare earth resources has been studied to synthesize $La_{0.5}Nd_{0.5}Ni_5$ alloy in a LiCl molten salt. The $Nd_2O_3-La_2O_3-NiO$ mixed oxide was converted to $NiNd_2O_4$ (spinel) and $LaNiO_3$ (perovskite) structures at a sintering temperature of $1100^{\circ}C$. The spinel and perovskite structures led a speed-up in the electrolytic reduction of the mixed oxide. Various reaction intermediates such as Ni, $NiLa_2O_4$ were observed during the electrochemical reduction by XRD analysis. A possible reaction route to $La_{0.5}Nd_{0.5}Ni_5$ in the LiCl molten salt was proposed based on the analysis result.

Mechanochemical Synthesis of LaNiO3 Crystalline Phase from Mixture of La2O3sub> and NiO (La2O3의 메카노케미컬 합성에 의한 LaNiO3결정상 생성)

  • 김대영;김강언;이명교;정수태
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.16 no.8
    • /
    • pp.681-687
    • /
    • 2003
  • The syntheses of LaNiO$_3$Perovskite crystalline phase from mixtures of La$_2$O$_3$and NiO via it mechanochemical(used planetary mill) and a wet ball mill process were investigated. A single and stable LaNiO$_3$perovskite crystalline phase was successfully prepared by using a heat free mechanochemical process which produced a fine amorphous powder, while that phase was not formed in a wet ball mill process which needed heat treatment ranging from 500 to 150$0^{\circ}C$ and produced a coarse powder. It was shown that the LaNiO$_3$ceramics made of the mechanochemically synthesized powder possesed a good metallic characteristic.

Effect of La in Partial Oxidation of Methane to Hydrogen over M(1)-Ni(5)/AlCeO3 (M = La, Ce, Y) Catalysts (M(1)-Ni(5)/AlCeO3 (M = La, Ce, Y) 촉매상에서 수소 제조를 위한 메탄의 부분산화반응에서 La의 효과)

  • Seo, Ho Joon
    • Applied Chemistry for Engineering
    • /
    • v.30 no.6
    • /
    • pp.757-761
    • /
    • 2019
  • The catalytic yields of POM to hydrogen over M(1)-Ni(5)/AlCeO3 (M = La, Ce, Y) were investigated using a fixed bed flow reactor under atmosphere. The crystal phase behavior of reduced La(1)-Ni(5)/AlCeO3 catalysts before and after the reaction were studied via XRD analysis. FESEM and EDS analyses were further performed to show the uniformed distribution of La, Ni, and Ce metal particles on the catalyst surface. XPS results showed O2-, O22- species and metal ions such as Ce3+, Ce4+, La3+ and Ni2+ etc. were on the catalyst surface. When 1 wt% of La was added to Ni(5)/AlCeO3 catalyst, Ni2p3/2 and Ce3d5/2 increased 52.7 and 6.3%, respectively. The yield of hydrogen on the La(1)-Ni(5)/AlCeO3 catalyst was 89.1%, which was much better than that of M(1)-Ni(5)/AlCeO3 (M = Ce, Y). As Ce4+ ions of CeO2 produced by the reaction of AlCeO3 with oxygen were substitute to La3+, it made oxygen vacancies in the lattice and further improved the hydrogen yield by increasing the dispersion of Ni atoms with strong metal-support interaction (SMSI) effect.

Characterization of NiO and Co3O4-Doped La(CoNi)O3 Perovskite Catalysts Synthesized from Excess Ni for Oxygen Reduction and Evolution Reaction in Alkaline Solution (과량의 니켈 첨가로 합성된 NiO와 Co3O4가 도핑된 La(CoNi)O3 페로브스 카이트의 알칼리용액에서 산소환원 및 발생반응 특성)

  • BO, LING;RIM, HYUNG-RYUL;LEE, HONG-KI;PARK, GYUNGSE;SHIM, JOONGPYO
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.32 no.1
    • /
    • pp.41-52
    • /
    • 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.

The Effect of La2O3 Loading on the Performance of Ni-La2O3-Ce0.8Zr0.2O2 Catalysts for Steam Reforming of Methane (수증기 개질 반응에서 Ni-La2O3-Ce0.8Zr0.2O2 촉매의 La2O3 함량이 촉매의 성능에 미치는 영향)

  • YOO, SEONG-YEUN;KIM, HAK-MIN;KIM, BEOM-JUN;JANG, WON-JUN;ROH, HYUN-SEOG
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.29 no.5
    • /
    • pp.419-426
    • /
    • 2018
  • $Ni-La_2O_3-Ce_{0.8}Zr_{0.2}O_2$ catalysts with various $La_2O_3$ loading were investigated for hydrogen production from steam reforming of methane (SRM). The $La_2O_3$ loading influenced the physicochemical properties of $Ni-La_2O_3-Ce_{0.8}Zr_{0.2}O_2$ catalysts such as BET surface area, Ni dispersion, Ni size and reducibility. Among the prepared catalysts, $Ni-70La_2O_3-Ce_{0.8}Zr_{0.2}O_2$ catalyst showed the highest activity and stability at a very high gas hourly space velocity (GHSV) of $932,556h^{-1}$. This is mainly due to high Ni dispersion, small Ni size and high reducibility.

Synthesis and Conductivity Properties of $LaNiO_3$ Ceramic Conductors ($LaNiO_3$전도성 세라믹의 합성과 도전특성)

  • Cho, Jung-Ho;Cho, Joo-Hun;Kim, Kang-Eun;Chung, Su-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • /
    • pp.406-409
    • /
    • 2001
  • The conductivity properties and synthesis of $LaNiO_{3}$ ceramics from $La_{1+\delta}NiO_{3}(\delta=-0.06,0,0.06)$ were investigated. A single perovskite phase was realized at $800^{\circ}C$. $La_{2}NiO_{4}$ and other unexpected oxide were observed at $1000^{\circ}C$. The Microstructure was showed clearly that it is a low density porous material. $LaNiO_3$ ceramic showed a metallic conductivity. The conductivity of La rich samples had a higher value than the La poor samples.

  • PDF

Synthesis and Conductivity Properties of LaNiO$_3$ Ceramic Conductors (LaNiO$_3$전도성 세라믹의 합성과 도전특성)

  • 조정호;조주현;김강언;정수태
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • /
    • pp.406-409
    • /
    • 2001
  • The conductivity properties and synthesis of LaNiO$_3$ ceramics from La$\sub$1+$\delta$/NiO$_3$($\delta$=--0.06, 0, 0.06) were investigated. A single perovskite phase was realized at 800$^{\circ}C$. La$_2$NiO$_4$ and other unexpected oxide were observed at 1000$^{\circ}C$. The Microstructure was showed clearly that it is a low density porous material. LaNiO$_3$ ceramic showed a metallic conductivity. The conductivity of La rich samples had a higher value than the La poor samples.

  • PDF

Low temperature synthesis of $LaNiO_3$ crystalline phase via oxide powder technology (산화물 합성법에 의한 $LaNiO_3$ 결정상의 저온합성)

  • Kim, Dae-Young;Jeong, Jae-Hoon;Son, Se-Mo;Kim, Kang-Eun;Chung, Su-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • /
    • pp.218-223
    • /
    • 2002
  • Low temperature synthesis of $LaNiO_3$ crystalline phase composited from mixtures of $La_2O_3$ and NiO via the ball mill and mechanochemical process were investigated. By the ball mill, 20% of $LaNiO_3$ crystalline phase was formed in the samples sintered at $900^{\circ}C$ due to the lack of reactivity of NiO. However, the mechanochemical process yielded about 93% of $LaNiO_3$ crystalline phase in room temperature.

  • PDF

The Effect of Carrier in CO2 Reforming of CH4 to Syngas over Ni-based catalysts

  • Seo, Ho Joon;Kang, Ung Il;Yu, Eui Yeon
    • Clean Technology
    • /
    • v.5 no.2
    • /
    • pp.63-68
    • /
    • 1999
  • The activities of Ni(20wt%)/$La_2O_3$, Ni(20wt%)/${\gamma}-Al_2O_3$, and Ni(20wt%)/$SiO_2$ catalyst for $CO_2$ reforming of $CH_4$ were investigated in a fixed bed flow reactor under atmospheric condition. Catalyst characterization using XRD, TEM, SEM, BET analysis were also conducted. The catalytic activity of Ni(20wt%)/$La_2O_3$ catalyst has relatively superior to that of Ni(20wt%)/${\gamma}-Al_2O_3$ and Ni(20wt%)/$SiO_2$ catalyst. The good activity of Ni(20wt%)/$La_2O_3$ catalyst seems to depend on reduced $Ni^{\circ}$ phases of NiO($\rightarrow$ Ni + O), $LaNiO_3$($\rightarrow$ $Ni+La_2O_3$), Ni crystalline phases, and decoration of Ni phases by lanthanum species is also an important factor. Ni(20wt%)/${\gamma}-Al_2O_3$ and Ni(20wt%)/$SiO_2$ catalyst due to surface acidity resulted in the deposition of wisker type and encapsulate carbon on the surface of catalyst, but Ni(20wt%)/$La_2O_3$ catalyst did not show carbon on the surface of catalyst up to 8.5hr reaction.

  • PDF

Electrochemical Properties of La4Ni3O10-GDC Composite Cathode by Facile Sol-gel Method for IT-SOFCs

  • Choi, Sihyuk;Kim, Guntae
    • Journal of the Korean Ceramic Society
    • /
    • v.51 no.4
    • /
    • pp.265-270
    • /
    • 2014
  • Among the Ruddlesden-Popper series, $La_4Ni_3O_{10}$ has received widespread attention as a promising cathode material by reason of its favorable properties for realizing high performance of intermediate temperature solid oxide fuel cells (IT-SOFCs). The $La_4Ni_3O_{10}$ cathode is prepared using the facile sol-gel method by employing tri-blockcopolymer (F127) to obtain a single phase in a short sintering time. There are no reactions between the $La_4Ni_3O_{10}$ cathode and the $Ce_{0.9}Gd_{0.1}O_{2-\delta}$ (GDC) electrolyte upon sintering at $1000^{\circ}C$, indicating that the $La_4Ni_3O_{10}$ cathode has good chemical compatibility with the GDC electrolyte. The maximum electrical conductivity of $La_4Ni_3O_{10}$ reaches approximately 240 S $cm^{-1}$ at $100^{\circ}C$ and gradually decreases with increasing temperaturein air atmosphere. The area specific resistance value of $La_4Ni_3O_{10}$ composite with 40 wt% GDC is $0.435{\Omega}cm^2$ at $700^{\circ}C$. These data allow us to propose that the $La_4Ni_3O_{10}$-GDC composite cathode is a good candidate for IT-SOFC applications.