在性介质中实现出色的氧化反应性能
Fei Yang1,2,3, Yian Wang2, Yingdan Cui2
1Eastern Institute for Advanced Study, Eastern Institute of Technology, Ningbo 315200, Zhejiang, China.
Journal of the American Chemical Society
|December 6, 2023
概括
研究人员使用简单的浸方法开发了3nm以下的Pt@Ru核心外纳米粒子. 这些先进的电催化剂显著提高了交换膜燃料电池 (AEMFC) 的氧化反应动力.
科学领域:
- 材料科学
- 电化学
- 纳米技术
背景情况:
- 阳离子交换膜燃料电池 (AEMFC) 对转化具有前景,但由于基介质中的缓慢氧化反应动力学而面临挑战.
- 开发高效的电催化剂对于推进AEMFC技术至关重要.
研究的目的:
- 合成高活性且稳定的3nm以下Pt@Ru核心外纳米粒子.
- 改善AEMFC中的氧化反应动力学.
- 展示先进的纳米催化剂的简单合成方法.
主要方法:
- 采用简单的浸工艺,在不同的回火温度下顺序减少 (Pt) 和 (Ru),生成Pt@Ru核心外纳米粒子.
- 描述了合成的纳米粒子的大小,结构和电化学表面积 (ECSA).
- 使用旋转盘电极 (RDE) 测量和膜电极组件 (MEA) 测试评估电催化剂性能.
主要成果:
- 合成的超小Pt@Ru核心外纳米粒子平均尺寸为2.5nm,高ECSA为166.66m2g.
- 实现的交换电流密度 (j0) 比商业Pt/C高8.0和5.8倍,质量正常化的j0是迄今为止报告的最高值.
- 在MEA测试中显示出1.78Wcm-2的峰值功率密度,超过商业PtRu/C.
结论:
- 简单的浸方法有效合成精细的Pt@Ru核心外纳米催化剂.
- 这种增强的活性归因于从Ru转移到Pt以及超细颗粒的大小.
- 这项工作突出了核心纳米结构提高AEMFC性能和原子结构控制的重要性.
相关概念视频
Reduction of Alkenes: Catalytic Hydrogenation
12.1K
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...
12.1K
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.3K
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...
3.3K
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
7.7K
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.
7.7K
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
1.8K
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
1.8K
Alcohols from Carbonyl Compounds: Reduction
10.4K
Reduction is a simple strategy to convert a carbonyl group to a hydroxyl group. The three major pathways to reduce carbonyls to alcohols are catalytic hydrogenation, hydride reduction, and borane reduction.
Catalytic hydrogenation is similar to the reduction of an alkene or alkyne by adding H2 across the pi bond in the presence of transition metal catalysts like Raney Ni, Pd–C, Pt, or Ru. Aldehydes and ketones can be reduced by this method, often under mild to moderate heat (25–100°C) and...
Catalytic hydrogenation is similar to the reduction of an alkene or alkyne by adding H2 across the pi bond in the presence of transition metal catalysts like Raney Ni, Pd–C, Pt, or Ru. Aldehydes and ketones can be reduced by this method, often under mild to moderate heat (25–100°C) and...
10.4K
Catalysis
27.0K
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.
27.0K


