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学科主题: 化学
题名: Funding for Clean Energy R&D by the Chinese Academy of Sciences
作者: Bao XH(包信和)
会议文集: Proceedings of PACIFICHEM 2010
会议名称: 2010 International Chemical Congress of Pacific Basin Societies
会议日期: 2010-12-15
出版日期: 2011
会议地点: 夏威夷
通讯作者: 包信和
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: 502
主办者: 美国化学会
摘要: In the present talk, the unique characters of the catalysis with the nano-confined system will be demonstrated, and the emphasis will be laid on the differences of the electron properties, which derived from a so-called effect of the quantum well states in the 2D nano-systems and the effects of the interface confinement between the nano-islands and the surfaces of the substrates. The effect of electron quantum confinement on the catalytic activities of 2D ultra-thin metal films is explored by comparing the work function change and the initial reaction rate of atomically flat films of different thickness on silicon surfaces, using complementary microscopy and spectroscopy techniques. The obvious oscillations of the oxidation rate of lead films are observed, which are attributed to be a manifestation of the Fabry-Pe´rot interference modes of electron de Broglie waves (quantum well states) in the films. The modulation of the electron density of states near the Fermi level opens a new demission for tuning the catalytic performance of metal systems via size- and thickness-dependent quantum size effects, which will be illustrated through two examples. Coordinatively unsaturated ferrous (CUF) sites confined in nanosized matrices are active centers in a wide range of enzyme and homogeneous catalytic reactions. Preparation of the analogous active sites at supported catalysts is of great importance in heterogeneous catalysis but remains a challenge. On the basis of surface science measurements and density functional calculations, in the present talk, I will show that the interface confinement effect can be used to stabilize the CUF sites by taking advantage of strong adhesion between ferrous oxides and metal substrates. The interface-confined CUF sites together with the metal supports are active for dioxygen activation, producing reactive dissociated oxygen atoms. The structural ensemble was highly efficient for carbon monoxide oxidation at low temperature under typical operating conditions of a proton-exchange membrane fuel cell. Carbon materials have properties different from conventional oxides in catalysis, in particular as catalyst supports. Recently, carbon nanotubes (CNTs) interest us with their well defined tubular morphology and their electron structure in the graphene walls, where π electrons shift from the inside to the outside due to the curvature. This provides an intriguing confinement environment for nanocatalysts and catalytic reactions inside such small cavities. In the present talk, the unique effects of the electron confinement with CNT’s and the resulted modulating in catalysis will be illustrated. The techniques to introduce metal nanoparticles homogeneously inside the CNT channels has been developed and the effects of confined metal catalysts on their physio-chemical properties, as well as their catalytic activities have been studied systematically. Using Fe as a probe, it is found that the redox properties of iron oxide and metallic iron are modified when they are confined inside the CNT channels. For example, the reduction of the CNT confined iron oxide is facilitated compared to that dispersed on the outer surface of CNTs. In this way, a distinct enhancement of the CNT encapsulated Fe species to the F-T process has also been revealed, which is attributed the favourable formation of the reduced iron species, e.g. iron carbides, inside the channel of CNTs. A striking enhancement of the catalytic activity of Rh particles confined inside nanotubes for the conversion of CO and H2 to ethanol has been found. The overall formation rate of ethanol inside nanotubes exceeds that on the outside of the nanotubes by more than an order of magnitude, although the latter is much better accessible. Selected Publications: 1. Textural Manipulation of Mesoporous Materials for Hosting of Metallic Nanocatalysts, Junming Sun and Xinhe Bao CHEMISTRY-A EUROPEAN JOURNAL (Invited Concept article), (2008)(14)7478-7488 2. eactivities, Xucun Ma, Peng Jiang, Yun Qi, Jinfeng Jia, Yu Yang, Wenhui Duan, Wei-Xue Li, Xinhe Bao, S. B. Zhang and Qi-Kun Xue, P NATL ACAD SCI USA (PNAS), 104(2007)(22)9204-9208 3. Towards Monodispersed Silver Nanoparticles with Unusual Thermal Stability, Junming Sun, Ding Ma, He Zhang, Xiumei Liu, Xiuwen Han, Xinhe Bao*, Gisela Weinberg, Norbert Pfaender, Dangsheng Su, J. Am. Chem. Soc., 128 (49) (2006) 15756-15764 4. Interface-Confined Ferrous Centres for Catalytic Oxidation, Qiang Fu, Wei-Xue Li1, Yunxi Yao, Hongyan Liu, Hai-Yan Su1, Ding Ma, Xiang-Kui Gu, Limin Chen, Zhen Wang, Hui Zhang, Bing Wang and Xinhe Bao*, Science, 328(2010)1141-1144 5. Effect of Confinement in Carbon Nanotubes on the Activity of Fischer-Tropsch Iron Catalyst, Wei Chen, Zhongli Fan, Xiulian Pan,* and Xinhe Bao*, J. Am. Chem. Soc., 130(2008)(29)9414-9419 6. Reactions over catalysts confined in carbon nanotubes, Xiulian Pan, Xinhe Bao, Chem. Commun., (Invited Feature Article) (2008)6271-6281 7. Enhanced Ethanol Production inside Carbon Nanotube Reactors Containing Catalytic Particles, Xiulian Pan, Zhongli Fan, Wei Chen, Yunjie Ding, Hongyuan Luo, Xinhe Bao*, Nature Materials, 6(2007)507-511 8. Tuning of redox properties of iron and iron oxides via encapsulation within carbon nanotubes, Wei Chen, Xiulian Pan, Xinhe Bao*, J. Am. Chem. Soc., 129(2007)(23)7421-7426 9. Facile Autoreduction of Iron Oxide/Carbon Nanotube Encapsulates, Wei Chen, Xiulian Pan, Marc-Georg Willinger, Dang Sheng Su, and Xinhe Bao*, J. Am. Chem. Soc., 128 (10) (2006) 3136-3137
英文摘要: In the present talk, the unique characters of the catalysis with the nano-confined system will be demonstrated, and the emphasis will be laid on the differences of the electron properties, which derived from a so-called effect of the quantum well states in the 2D nano-systems and the effects of the interface confinement between the nano-islands and the surfaces of the substrates. The effect of electron quantum confinement on the catalytic activities of 2D ultra-thin metal films is explored by comparing the work function change and the initial reaction rate of atomically flat films of different thickness on silicon surfaces, using complementary microscopy and spectroscopy techniques. The obvious oscillations of the oxidation rate of lead films are observed, which are attributed to be a manifestation of the Fabry-Pe´rot interference modes of electron de Broglie waves (quantum well states) in the films. The modulation of the electron density of states near the Fermi level opens a new demission for tuning the catalytic performance of metal systems via size- and thickness-dependent quantum size effects, which will be illustrated through two examples. Coordinatively unsaturated ferrous (CUF) sites confined in nanosized matrices are active centers in a wide range of enzyme and homogeneous catalytic reactions. Preparation of the analogous active sites at supported catalysts is of great importance in heterogeneous catalysis but remains a challenge. On the basis of surface science measurements and density functional calculations, in the present talk, I will show that the interface confinement effect can be used to stabilize the CUF sites by taking advantage of strong adhesion between ferrous oxides and metal substrates. The interface-confined CUF sites together with the metal supports are active for dioxygen activation, producing reactive dissociated oxygen atoms. The structural ensemble was highly efficient for carbon monoxide oxidation at low temperature under typical operating conditions of a proton-exchange membrane fuel cell. Carbon materials have properties different from conventional oxides in catalysis, in particular as catalyst supports. Recently, carbon nanotubes (CNTs) interest us with their well defined tubular morphology and their electron structure in the graphene walls, where π electrons shift from the inside to the outside due to the curvature. This provides an intriguing confinement environment for nanocatalysts and catalytic reactions inside such small cavities. In the present talk, the unique effects of the electron confinement with CNT’s and the resulted modulating in catalysis will be illustrated. The techniques to introduce metal nanoparticles homogeneously inside the CNT channels has been developed and the effects of confined metal catalysts on their physio-chemical properties, as well as their catalytic activities have been studied systematically. Using Fe as a probe, it is found that the redox properties of iron oxide and metallic iron are modified when they are confined inside the CNT channels. For example, the reduction of the CNT confined iron oxide is facilitated compared to that dispersed on the outer surface of CNTs. In this way, a distinct enhancement of the CNT encapsulated Fe species to the F-T process has also been revealed, which is attributed the favourable formation of the reduced iron species, e.g. iron carbides, inside the channel of CNTs. A striking enhancement of the catalytic activity of Rh particles confined inside nanotubes for the conversion of CO and H2 to ethanol has been found. The overall formation rate of ethanol inside nanotubes exceeds that on the outside of the nanotubes by more than an order of magnitude, although the latter is much better accessible. Selected Publications: 1. Textural Manipulation of Mesoporous Materials for Hosting of Metallic Nanocatalysts, Junming Sun and Xinhe Bao CHEMISTRY-A EUROPEAN JOURNAL (Invited Concept article), (2008)(14)7478-7488 2. eactivities, Xucun Ma, Peng Jiang, Yun Qi, Jinfeng Jia, Yu Yang, Wenhui Duan, Wei-Xue Li, Xinhe Bao, S. B. Zhang and Qi-Kun Xue, P NATL ACAD SCI USA (PNAS), 104(2007)(22)9204-9208 3. Towards Monodispersed Silver Nanoparticles with Unusual Thermal Stability, Junming Sun, Ding Ma, He Zhang, Xiumei Liu, Xiuwen Han, Xinhe Bao*, Gisela Weinberg, Norbert Pfaender, Dangsheng Su, J. Am. Chem. Soc., 128 (49) (2006) 15756-15764 4. Interface-Confined Ferrous Centres for Catalytic Oxidation, Qiang Fu, Wei-Xue Li1, Yunxi Yao, Hongyan Liu, Hai-Yan Su1, Ding Ma, Xiang-Kui Gu, Limin Chen, Zhen Wang, Hui Zhang, Bing Wang and Xinhe Bao*, Science, 328(2010)1141-1144 5. Effect of Confinement in Carbon Nanotubes on the Activity of Fischer-Tropsch Iron Catalyst, Wei Chen, Zhongli Fan, Xiulian Pan,* and Xinhe Bao*, J. Am. Chem. Soc., 130(2008)(29)9414-9419 6. Reactions over catalysts confined in carbon nanotubes, Xiulian Pan, Xinhe Bao, Chem. Commun., (Invited Feature Article) (2008)6271-6281 7. Enhanced Ethanol Production inside Carbon Nanotube Reactors Containing Catalytic Particles, Xiulian Pan, Zhongli Fan, Wei Chen, Yunjie Ding, Hongyuan Luo, Xinhe Bao*, Nature Materials, 6(2007)507-511 8. Tuning of redox properties of iron and iron oxides via encapsulation within carbon nanotubes, Wei Chen, Xiulian Pan, Xinhe Bao*, J. Am. Chem. Soc., 129(2007)(23)7421-7426 9. Facile Autoreduction of Iron Oxide/Carbon Nanotube Encapsulates, Wei Chen, Xiulian Pan, Marc-Georg Willinger, Dang Sheng Su, and Xinhe Bao*, J. Am. Chem. Soc., 128 (10) (2006) 3136-3137
内容类型: 会议论文
URI标识: http://cas-ir.dicp.ac.cn/handle/321008/115906
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:
Bao XH. Funding for Clean Energy R&D by the Chinese Academy of Sciences[C]. 见:2010 International Chemical Congress of Pacific Basin Societies. 夏威夷. 2010-12-15.
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