Direct Microstructural Evidence on the Catalyzing Mechanism for De/hydrogenation of Mg by Multi-valence NbOx
作者:Liu, JW (Liu, Jiangwen)[ 1 ] ; Fu, YY (Fu, Yiyuan)[ 1 ] ; Huang, WC (Huang, Wencheng)[ 1 ] ; Wang, H (Wang, Hui)[ 1 ] ; Ouyang, LZ (Ouyang, Liuzhang)[ 1 ] ; Zeng, MQ (Zeng, Meiqin)[ 1 ] ; Zhu, M (Zhu, Min)[ 1 ]
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JOURNAL OF PHYSICAL CHEMISTRY C
卷: 124 期: 12 页: 6571-6579
DOI: 10.1021/acs.jpcc.9b10344
出版年: MAR 26 2020
文献类型:Article
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摘要
To understand the catalyzing mechanism for hydrogenation/dehydrogenation of Mg by transition metals and their oxides, a series of Mg(100 nm)/NbOx(10 nm) multilayer films were designed and prepared to exactly regulate the types and valence of NbOx catalysts by magnetron sputtering. The intensive TEM and kinetic characterization on hydriding/dehydriding reactions of Mg gives direct detailed microstructure insight and leads to the catalyzing mechanism of the multi-valence NbOx. Compared to the single component catalyst, i.e., either Nb or Nb2O5, the hybrid catalysts of (Nb2O5 + Nb) exhibited a much superb catalyzing effect for de/hydrogenation of Mg. The Mg/(Nb2O5 + Nb) films can absorb more than 4 wt % H-2 within 15 min at 200 degrees C and can desorb 2.6 wt % H-2 within 50 min at 225 degrees C. Also, the hydrogenated Mg/(Nb2O5 + Nb) film presented the lowest hydrogen desorption temperature with the starting temperature at 132 degrees C and the peak temperature at 180 degrees C. According to the presence of a series of binary Nb-O compounds and ternary Nb-Mg-O compounds, which were verified via electron diffraction and high-resolution TEM(HRTEM), it is suggested that the multiple-valence Nb ions can act as an intermediate for the electron transferring between Mg/Mg2+ and H/H-. These intermediate NbOx compounds containing defects as well as Nb with good electroconductibility can reduce the activation energy barriers of MgH2/Mg reactions and make the reactions faster and easier.
关键词
KeyWords Plus:HYDROGEN STORAGE; IN-SITU; SORPTION; NB2O5; NANOPARTICLES; DESORPTION; KINETICS; HYDRIDE; TI
作者信息
通讯作者地址: Zhu, M (通讯作者)
显示更多South China Univ Technol, Sch Mat Sci & Engn, Guangdong Prov Key Lab Adv Energy Storage Mat, Guangzhou 510640, Peoples R China.
地址:
显示更多[ 1 ] South China Univ Technol, Sch Mat Sci & Engn, Guangdong Prov Key Lab Adv Energy Storage Mat, Guangzhou 510640, Peoples R China
电子邮件地址:memzhu@scut.edu.cn
基金资助致谢
基金资助机构显示详情授权号
National Key Research and Development Plan of China
2018YBF1502100
National Natural Science Foundation of China
51621001
National Natural Science Foundation of China
51571091
51871098
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出版商
AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
期刊信息
Impact Factor (影响因子): Journal Citation Reports
类别 / 分类
研究方向:Chemistry; Science & Technology - Other Topics; Materials Science
Web of Science 类别:Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary