...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Physical chemistry chemical physics: PCCP >Effects of deposited Pt particles on the reducibility of CeO2(111)
【24h】

Effects of deposited Pt particles on the reducibility of CeO2(111)

机译：沉积的Pt颗粒对CeO2（111）还原性的影响

获取原文
获取原文并翻译 | 示例
   

获取外文期刊封面封底 >>

       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The interaction of Pt particles with the regular CeO2(111) surface has been studied using Pt8 clusters as representative examples. The atomic and electronic structure of the resulting model systems have been obtained through periodic spin-polarized density functional calculations using the PW91 exchange-correlation potential corrected with the inclusion of a Hubbard U parameter. The focus is on the effect of the metal-support interaction on the surface reducibility of ceria. Several initial geometries and orientations of Pt8 with respect to the ceria substrate have been explored. It has been found that deposition of Pt8 over the ceria surface results in spontaneous oxidation of the supported particle with a concomitant reduction of up to two Ce~(4+) cations to Ce~(3+). Oxygen vacancy formation on the CeO2(111) surface and oxygen spillover to the adsorbed particle have also been considered. The presence of the supported Pt8 particles has a rather small effect (~0.2 eV) on the O vacancy formation energy. However, it is predicted that the spillover of atomic oxygen from the substrate to the metal particle greatly facilitates the formation of oxygen vacancies: the calculated energy required to transfer an oxygen atom from the CeO2(111) surface to the supported Pt8 particle is only 1.00 eV, i.e. considerably smaller than 2.25 eV necessary to form an oxygen vacancy on the bare regular ceria surface. This strongly suggests that the propensity of ceria systems to store and release oxygen is directly affected by the presence of supported Pt particles.
机译：以Pt8团簇为代表研究了Pt颗粒与规则CeO2（111）表面的相互作用。通过使用包含Hubbard U参数校正的PW91交换相关电势，通过周期性自旋极化密度函数计算获得了所得模型系统的原子和电子结构。重点是金属-载体相互作用对二氧化铈表面还原性的影响。已经研究了Pt8相对于二氧化铈底物的几种初始几何形状和取向。已经发现，Pt8在二氧化铈表面上的沉积导致负载颗粒的自发氧化，伴随着最多两个Ce〜（4+）阳离子还原为Ce〜（3+）。还考虑了在CeO2（111）表面形成氧空位和氧溢出到吸附颗粒上。负载的Pt8颗粒的存在对O空位形成能的影响很小（〜0.2 eV）。但是，可以预见的是，原子氧从衬底到金属粒子的溢出会大大促进氧空位的形成：将氧原子从CeO2（111）表面转移到负载的Pt8粒子所需的计算能量仅为1.00 eV，即大大小于在裸露的规则二氧化铈表面上形成氧空位所需的2.25 eV。这强烈表明二氧化铈系统储存和释放氧气的倾向直接受到负载的Pt颗粒的影响。

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