• Title/Summary/Keyword: materials science

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Size control of Co-doped ZnO rods by changing the solvent

  • Zhao, Jing;Yan, Xiaoqin;Lei, Yang;Zhao, Yanguang;Huang, Yunhua;Zhang, Yue
    • Advances in materials Research
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    • v.1 no.1
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    • pp.75-81
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    • 2012

  • In this work, the Co-doped ZnO rods were prepared by the hydrothermal method. The size of these rods can be changed from micro-size to nano-size by using different solutions during the preparation. The results of transmission electron microscopy (TEM) and selected area electron diffraction (SAED) showed that the as-prepared nano-sized Co-doped rods have single-crystal structure. The polarized Raman experiments were presented on an individual micro-sized Co-doped ZnO rod in the $X(YY)\vec{X}$, $X(ZY)\vec{X}$ and $X(ZZ)\vec{X}$ configurations, the results of polarized Raman indicated that these rods are crystallized and their growth direction is parallel to c-axis.

  • https://doi.org/10.12989/amr.2012.1.1.075 인용 KSCI

Influence of Reaction Conditions on the Grafting Pattern of 3-Glycidoxypropyl trimethoxysilane on Montmorillonite

  • He, Wentao;Yao, Yong;He, Min;Kai, Zhang;Long, Lijuan;Zhang, Minmin;Qin, Shuhao;Yu, Jie
    • Bulletin of the Korean Chemical Society
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    • v.34 no.1
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    • pp.112-116
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    • 2013

  • Surface modification of montmorillonite (MMT) with 3-glycidoxypropyl trimethoxysilane (3GTO) in mild methanol/water mixture has been investigated in detail. The influence of reaction conditions (including silane concentration in feed, reaction time and reaction temperature) on the grafting amount and yield of silane, and further on the grafting pattern of silanes was studied by thermogravimetric analysis, elemental analysis, X-ray diffraction (XRD) and BET. Higher silane concentration, longer reaction time and higher reaction temperature are all benefit to higher grafting amount. When the grafting reaction was performed with 3 mmol/g silane concentration, at $90^{\circ}C$ for 24 h, the grafted amount and yield of silane reached 1.4443 mmol/g and 30%, respectively. Based on the XRD and BET data analysis, a speculation that the grafting pattern of silanes was concentration dependence was proposed.

  • https://doi.org/10.5012/bkcs.2013.34.1.112 인용 PDF KSCI

Synthesis and characterization of NiFe2O4 nanoparticle electrocatalyst for urea and water oxidation (요소 산화반응을 위한 NiFe2O4 나노파티클 촉매 합성 및 특성 분석 )

  • Ki-Yong Yoon;Kyung-Bok Lee;Dohyung Kim;Hee Yoon Roh;Sung Mook Choi;Ji-hoon Lee;Jaehoon Jeong;Juchan Yang
    • Journal of the Korean institute of surface engineering
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    • v.56 no.4
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    • pp.243-249
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    • 2023

  • Urea oxidation reaction (UOR) via electrochemical oxidation process can replace oxygen evolution reaction (OER) for green hydrogen production since UOR has lower thermodynamic potential (0.37 VRHE) than that of OER (1.23 VRHE). However, in the case of UOR, 6 electrons are required for the entire UOR. For this reason, the reaction rate is slower than OER, which requires 4 electrons. In addition, it is an important challenge to develop catalysts in which both oxidation reactions (UOR and OER) are active since the active sites of OER and UOR are opposite to each other. We prove that among the NiFe2O4 nanoparticles synthesized by the hydrothermal method at various synthesis temperatures, NiFe2O4 nanoparticle with properly controlled particle size and crystallinity can actively operate OER and UOR at the same time.

  • https://doi.org/10.5695/JSSE.2023.56.4.243 인용 PDF