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学科主题: 物理化学
题名: Selective production of 1,2-propylene glycol from Jerusalem artichoke tuber on Ni-W2C/AC catalysts
作者: Zhou LK(周立坤) ;  Wang AQ(王爱琴) ;  Zhang T(张涛)
会议文集: Selective production of 1,2-propylene glycol from Jerusalem artichoke tuber on Ni-W2C/AC catalysts
会议名称: 1st International Congress on Catalysis for Biorefineries
会议日期: 2011-10-2
出版日期: 2011
会议地点: 马拉加
通讯作者: 张涛
出版者: 待补充
出版地: 待补充
合作性质: 分会特邀报告
部门归属: 1501
主办者: UNIVERSIDAD DE MALAGA
摘要: Gold-based bimetallic nanoparticles are emerging as a type of efficient catalysts in a variety of important reactions including low-temperature CO oxidation, epoxidation of propene, hydrogenation of oxygen to produce hydrogen peroxide, and selective oxidation of alcohols to aldehydes or ketones. For gold-based bimetallic nanocatalysts, control of particle size, structure, as well as composition is of crucial importance to the catalytic performance. In the present work, we prepared highly dispersed Au-Ag and Au-Cu bimetallic nanoparticles with uniform sizes of 2-3 nm and tunable chemical compositions on silica gel by a two-step method. More intriguing, the bimetallic nanoparticles present excellent thermal stabilities; no significant sintering occurred even after calcination in air at 500-600 oC, which is much superior to monometallic gold catalysts. Low-temperature CO oxidation tests showed that both the Au-Ag and Au-Cu bimetallic nanocatalysts exhibited much higher activities than their monometallic counterparts, and the catalytic activities are critically dependent on the Au/Ag or Au/Cu ratios, demonstrating the synergistic effect between Au and the second metal. To uncover the underlying reason for the superior thermal stability and exceptionally high activity of the gold-based bimetallic nanocatalysts, a variety of in situ techniques were employed, including XRD, UV-Vis, EPR, XANES, and FT-IR. With Au-Cu as an example, the results showed that upon calcination at high temperatures, the Cu component is segregated on the surface, forming patches or a layer of CuO on the gold core. It is such a thin layer or patches of CuO on the surface that prevents the gold nanoparticles from sintering. After being pretreated (activated) with H2 at a high temperature, a part of the CuO was reduced into metallic Cu0 and diffused into gold core to form Au3Cu1 alloy phase, while the other part of CuO which was directly interacted with the support was only reduced to Cu+ acting as the nanoglue between Au3Cu1 particles and the support. During CO oxidation, the Cu0 component was again enriched on the surface forming CuOx tiny patches on the gold surface, thus maximizing the perimeter between gold and CuOx. CO adsorbed on gold reacts with the active oxygen provided by the neighboring CuOx, in this way the catalytic activity was enhanced greatly in comparison with monometallic gold.
英文摘要: Gold-based bimetallic nanoparticles are emerging as a type of efficient catalysts in a variety of important reactions including low-temperature CO oxidation, epoxidation of propene, hydrogenation of oxygen to produce hydrogen peroxide, and selective oxidation of alcohols to aldehydes or ketones. For gold-based bimetallic nanocatalysts, control of particle size, structure, as well as composition is of crucial importance to the catalytic performance. In the present work, we prepared highly dispersed Au-Ag and Au-Cu bimetallic nanoparticles with uniform sizes of 2-3 nm and tunable chemical compositions on silica gel by a two-step method. More intriguing, the bimetallic nanoparticles present excellent thermal stabilities; no significant sintering occurred even after calcination in air at 500-600 oC, which is much superior to monometallic gold catalysts. Low-temperature CO oxidation tests showed that both the Au-Ag and Au-Cu bimetallic nanocatalysts exhibited much higher activities than their monometallic counterparts, and the catalytic activities are critically dependent on the Au/Ag or Au/Cu ratios, demonstrating the synergistic effect between Au and the second metal. To uncover the underlying reason for the superior thermal stability and exceptionally high activity of the gold-based bimetallic nanocatalysts, a variety of in situ techniques were employed, including XRD, UV-Vis, EPR, XANES, and FT-IR. With Au-Cu as an example, the results showed that upon calcination at high temperatures, the Cu component is segregated on the surface, forming patches or a layer of CuO on the gold core. It is such a thin layer or patches of CuO on the surface that prevents the gold nanoparticles from sintering. After being pretreated (activated) with H2 at a high temperature, a part of the CuO was reduced into metallic Cu0 and diffused into gold core to form Au3Cu1 alloy phase, while the other part of CuO which was directly interacted with the support was only reduced to Cu+ acting as the nanoglue between Au3Cu1 particles and the support. During CO oxidation, the Cu0 component was again enriched on the surface forming CuOx tiny patches on the gold surface, thus maximizing the perimeter between gold and CuOx. CO adsorbed on gold reacts with the active oxygen provided by the neighboring CuOx, in this way the catalytic activity was enhanced greatly in comparison with monometallic gold.
语种: 英语
内容类型: 会议论文
URI标识: http://cas-ir.dicp.ac.cn/handle/321008/115995
Appears in Collections:中国科学院大连化学物理研究所_会议论文

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Recommended Citation:
Zhou LK,Wang AQ,Zhang T. Selective production of 1,2-propylene glycol from Jerusalem artichoke tuber on Ni-W2C/AC catalysts[C]. 见:1st International Congress on Catalysis for Biorefineries. 马拉加. 2011-10-2.
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