在金属间纳米结构中孤立的单原子Pd位点:高催化选择性用于类的半化
Quanchen Feng1, Shu Zhao1, Yu Wang2
1Department of Chemistry, Tsinghua University , Beijing 100084, China.
Journal of the American Chemical Society
|May 16, 2017
概括
在金属间结构中设计单原子 (Pd) 位点显著提高了乙烯化的催化选择性. 这项研究强调PdIn (110) 表面的性能优于Pd3In (111) 表面.
科学领域:
- 材料科学
- 催化剂
- 表面化学
背景情况:
- 提高 (Pd) 催化剂的选择性对于工业应用至关重要,但仍然具有挑战性.
- 单原子催化剂具有提高选择性和稳定的独特特性.
- 金属间结构可以稳定单个Pd位点并提高催化性能.
研究的目的:
- 研究甲半化中的单原子Pd位点的催化选择性.
- 为了比较不同金属间表面的性能,特别是PdIn和Pd3In.
- 为合理设计双金属催化剂提供见解.
主要方法:
- 用密度函数理论 (DFT) 建模研究PdIn和Pd3In的电子和表面特性.
- 计算模型集中在Pm3̅m PdIn的 (110) 表面和P4/mm Pd3In的 (111) 表面上.
- 使用合成的金属间PdIn和Pd3In纳米晶体进行实验验证.
主要成果:
- 在Pm3̅m PdIn与单原子Pd位点的 (110) 表面上,DFT模型预测了对乙半化的高选择性.
- 在理论计算中,P4/mm Pd3In的111表面具有Pd剪切点的选择性较低.
- 实验结果证实,与Pd3In纳米晶体 (21%,暴露表面111) 相比,金属间PdIn纳米晶体的乙烯选择性在90°C时显著更高 (92%).
结论:
- 金属间PdIn结构,特别是那些暴露在单原子Pd位点的表面的结构,对乙烯化具有高度选择性.
- 特定的表面面和原子排列 (单原子与三元体) 极大地影响了催化选择性.
- 这项研究提供了一个设计策略,用于开发具有针对化学转换的定制选择性的高级双金属催化剂.
相关概念视频
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.9K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
3.9K
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
9.2K
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
9.2K
02:13Reduction of Alkenes: Catalytic Hydrogenation
14.5K
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
14.5K
01:22Heterogeneous Catalysis
9
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...
9
02:50Catalysis
31.1K
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
31.1K