• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Supported Copper, Nickel and Copper-Nickel Nanoparticle Catalysts for Low Temperature Water-Gas-Shift Reaction.
【24h】

Supported Copper, Nickel and Copper-Nickel Nanoparticle Catalysts for Low Temperature Water-Gas-Shift Reaction.

机译：用于低温水煤气变换反应的负载型铜，镍和铜-镍纳米颗粒催化剂。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Hydrogen is being considered worldwide as a future replacement for gasoline, diesel fuel, natural gas in both the transportation and non-transportation sectors. Hydrogen is a versatile energy carrier that can be produced from a variety of widely available primary energy sources, including coal, natural gas, biomass, solar, wind, and nuclear power. Coal, the most abundant fossil fuel on the planet, is being looked at as the possible future major source of H2, due to the development of the integrated gasification combined cycle (IGCC) and integrated gasification fuel cell technologies (IGFC). The gasification of coal produces syngas consisting of predominately carbon monoxide and hydrogen with some remaining hydrocarbons, carbon dioxide and water. Then, the water-gas shift reaction is used to convert CO to CO2 and additional hydrogen.;The present work describes the synthesis of model Cu, Ni and Cu-Ni catalysts prepared from metal colloids, and compares their behavior in the WGS reaction to that of traditional impregnation catalysts.;Initially, we systematically explored the performance of traditional Cu, Ni and Cu-Ni WGS catalysts made by impregnation methods. Various bimetallic Cu-Ni catalysts were prepared by supported impregnation and compared to monometallic Cu and Ni catalysts. The presence of Cu in bimetallic catalysts suppressed undesirable methanation side reaction, while the Ni component was important for high WGS activity.;Colloidal Cu, Ni and Cu-Ni alloy nanoparticles obtained by chemical reduction were deposited onto alumina to prepare supported catalysts. The resulting Cu and Ni nanoparticle catalysts were found to be 2.5 times more active in the WGS reaction per unit mass of active metal as compared to catalysts prepared by the conventional impregnation technique. The powder XRD and HAADF-STEM provided evidence supporting the formation of Cu-Ni particles containing the Cu core and Cu-Ni alloy shell. The XPS data indicated surface segregation of Cu in the bimetallic Cu-Ni catalysts after reduction. The colloidal Cu5Ni5 alloy catalyst exhibited the WGS reaction rate that was higher than that observed over colloidal Cu and Ni catalysts indicating for the very first time a favorable bimetallic effect for the Cu-Ni system. The presence of Cu in these bimetallic catalysts induced favorable structural and electronic effects not only for enhancing the WGS activity, but also for suppressing methane yield.;Bimetallic Cu-Ni catalysts possessing a core-shell structure were synthesized that provided important insights into their structure-activity relationships in the WGS reaction. We employed a successive reduction route to synthesize Cu Ni and Ni Cu core-shell nanoparticles and deposited them onto alumina support to obtain supported bimetallic catalysts. The powder XRD patterns, CO chemisorption data, and UV-vis spectra indicated the formation of core-shell structures in the bimetallic Cu-Ni nanoparticles. Cu Ni catalysts showed similar WGS activities to supported Ni catalysts but lower methanation activity. Suppressed methanation activity observed for Cu Ni nanoparticles may be due to Cu segregation to the surface. Supported Ni Cu catalysts displayed WGS activity comparable to supported Cu catalysts.;Therefore, these findings strongly suggested that supported Cu, Ni and Cu-Ni alloy nanoparticle catalysts prepared from metal colloids are very promising as highly active WGS catalysts.
机译：氢在全世界被认为是运输和非运输领域中汽油，柴油，天然气的未来替代品。氢是一种多用途的能源载体，可以从包括煤炭，天然气，生物质，太阳能，风能和核能在内的各种广泛的一次能源中生产。煤炭是地球上最丰富的化石燃料，由于集成气化联合循环（IGCC）和集成气化燃料电池技术（IGFC）的发展，正在被视为未来可能的H2主要来源。煤的气化产生合成气，主要由一氧化碳和氢气以及一些剩余的碳氢化合物，二氧化碳和水组成。然后，利用水煤气变换反应将CO转化为CO2和额外的氢气。;本工作描述了由金属胶体制备的模型Cu，Ni和Cu-Ni催化剂的合成，并比较了它们在WGS反应中的行为。最初，我们系统地探索了通过浸渍方法制备的传统Cu，Ni和Cu-Ni WGS催化剂的性能。通过负载浸渍制备了各种双金属Cu-Ni催化剂，并将其与单金属Cu和Ni催化剂进行了比较。双金属催化剂中Cu的存在抑制了不希望的甲烷化副反应，而Ni组分对于高WGS活性很重要。通过化学还原获得的胶体Cu，Ni和Cu-Ni合金纳米颗粒被沉积到氧化铝上以制备负载型催化剂。已发现，与通过常规浸渍技术制备的催化剂相比，每单位质量的活性金属在WGS反应中所得的Cu和Ni纳米颗粒催化剂的活性高2.5倍。 XRD和HAADF-STEM粉末提供了支持形成包含Cu核和Cu-Ni合金壳的Cu-Ni颗粒的证据。 XPS数据表明还原后双金属Cu-Ni催化剂中Cu的表面偏析。胶态Cu5Ni5合金催化剂的WGS反应速率高于在胶态Cu和Ni催化剂上观察到的WGS反应速率，这首次表明对Cu-Ni系统有利的双金属效应。这些双金属催化剂中Cu的存在不仅引起了良好的结构和电子效应，不仅增强了WGS活性，而且抑制了甲烷的产率。合成了具有核-壳结构的双金属Cu-Ni催化剂，为它们的结构提供了重要的见解-WGS反应中的活性关系。我们采用了连续的还原途径来合成Cu Ni和Ni Cu核壳纳米粒子，并将其沉积在氧化铝载体上以获得负载的双金属催化剂。粉末XRD图谱，CO化学吸附数据和UV-vis光谱表明在双金属Cu-Ni纳米颗粒中形成了核-壳结构。 Cu Ni催化剂显示出与负载Ni催化剂相似的WGS活性，但甲烷化活性较低。对于Cu Ni纳米颗粒观察到的甲烷化活性降低可能是由于Cu偏析在表面上。负载型Ni Cu催化剂具有与负载型Cu催化剂相当的WGS活性。因此，这些发现强烈表明由金属胶体制备的负载型Cu，Ni和Cu-Ni合金纳米颗粒催化剂作为高活性WGS催化剂非常有前途。

著录项

  • 作者

    Lin, Jiann-Horng.;

  • 作者单位

    University of Cincinnati.;

  • 授予单位 University of Cincinnati.;
  • 学科 Engineering Chemical.;Nanotechnology.;Energy.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 207 p.
  • 总页数 207
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号