...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, B. Condensed matter, materials, surfaces, interfaces & biophysical >Characterization of surface composition of platinum and ruthenium nanoalloys dispersed on active carbon
【24h】

Characterization of surface composition of platinum and ruthenium nanoalloys dispersed on active carbon

机译：活性炭上分散的铂和钌纳米合金表面成分的表征

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

Supported samples of 8 wt % monometallic Pt/C and Ru/C, as well as 12 wt % bimetallic Pt50Ru50/C, were prepared by the method of incipient wetness impregnation. Impregnated samples were subsequently reduced by hydrogen and then oxidized in air at different T,, temperatures. TEM and XRD examinations indicated that metal crystallites were finely dispersed with a diameter of d(M) >= 3 nm on the reduced samples. Reductive behavior of the oxidized samples by hydrogen was pursued with the technique of temperature programmed reduction (TPR). The temperature of the reduction peaks (T-r) noticed in the TPR profiles varied with the metal composition of catalysts and T-o temperature of oxidation. At T-o = 300 K, oxidation was confined to the surface layer of metallic crystallites. As a result, (PtO)-O-s (with a peak at T-r = 230 K) or PtsO(2) (T-r = 250 K) was formed on monometallic Pt/C while (RuO2)-O-s (T-r similar to 380 K) was formed on Ru/C. A reductive peak with T-r = 250 K was found from the bimetallic sample from Pt50Ru50/C oxidized at T-o = 300 K. The reductive peak suggests bimetallic crystallites were dispersed with cherry type structure, with Pt exposed at the surface and Ru in the core. On increasing the To temperature of oxidation treatment to 370 K and higher, T, peaks between 270 and 350 K were gradually noticed on the oxidized bimetallic sample. Peaks in this T, region are assigned to reduction of the oxidized alloy surface (A(s)O). Evidently, a segregation of Ru to the surface of the bimetallic crystallites is indicated upon oxidation at T-o > 380 K.
机译：通过初期湿润浸渍法制备了8wt％的单金属Pt / C和Ru / C以及12wt％的双金属Pt50Ru50 / C的负载样品。随后将浸渍的样品用氢气还原，然后在空气中以不同的温度进行氧化。 TEM和XRD检查表明，在还原的样品上，金属微晶以d（M）> = 3 nm的直径精细分散。用程序升温还原（TPR）技术追踪了被氢气氧化的样品的还原行为。 TPR曲线中发现的还原峰温度（T-r）随催化剂的金属组成和氧化的T-o温度而变化。在T ＝ 300K时，氧化被限制在金属微晶的表面层。结果，在单金属Pt / C上形成了（PtO）-Os（峰值位于Tr = 230 K）或PtsO（2）（Tr = 250 K），而（RuO2）-Os（Tr类似于380 K）在Ru / C上形成。从Pt50Ru50 / C在T-o = 300 K氧化的双金属样品中发现了一个T-r = 250 K的还原峰。该还原峰表明双金属晶体散布成樱桃型结构，Pt暴露在表面，Ru暴露在芯中。将氧化处理的To温度提高到370 K或更高时，在氧化的双金属样品上逐渐观察到T在270和350 K之间的峰。在该T，区域中的峰被指定为氧化合金表面（A（s）O）的还原。显然，在T-o> 380 K时，氧化表明Ru偏于双金属微晶的表面。

著录项

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