当地电荷转移揭示了氧化反应的高潜能的抗灭活
Hongda Shi1, Yang Yang1, Pin Meng1
1Hefei National Research Center for Physical Sciences at the Microscale and Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
Journal of the American Chemical Society
|June 5, 2024
概括
改性纳米颗粒与团增强性氧化反应 (HOR) 的活性和稳定性,克服了燃料电池性能的一个关键限制.
科学领域:
- 电化学
- 材料科学
- 催化剂
背景情况:
- (Ru) 基电催化剂用于性氧化反应 (HOR) 通常在高于0.1V的电位下表现出较低的活性,而可逆电极 (RHE) 则表现出较低的活性.
- 这种活动衰减归因于Ru纳米粒子过度充电和随后在更高的潜力下过度吸收氧气种,限制了燃料电池的寿命.
- 对于高效的燃料电池应用,开发适用于广泛潜力的稳定和活跃的HOR电催化剂至关重要.
研究的目的:
- 在性介质中保持高活性和稳定性的新型电催化剂的设计和合成.
- 研究改性催化剂在高电位下防止活动衰变的机制.
- 在氧化物交换膜燃料电池 (HEMFC) 中评估新催化剂的性能.
主要方法:
- 在碳 (MnOx(OH) y@Ru/C上合成氧化 (MnOx(OH) y) 集群修饰的纳米粒子.
- 使用循环电压测量和时电压测量等技术对HOR活性和稳定性的电化学表征.
- 在现场进行X射线吸收细结构 (XAFS) 分析,以探测催化剂在运行过程中的电子结构.
- 密度功能理论 (DFT) 计算以阐明Ru和Mn物种之间的催化机制和相互作用.
- 使用开发的催化剂制造和测试氧交换膜燃料电池 (HEMFC).
主要成果:
- MnOx(OH) y@Ru/C催化剂在广泛的电位窗口 (0-1.0V与RHE) 中显著增强了HOR活性和稳定性.
- 使用MnOx(OH) y@Ru/C阳极的HEMFC实现了高峰功率密度为1.731W cm-2,超过了标准基催化剂 (Pt/C).
- 现场XAFS和DFT计算证实Mn物种有效地接受过电的Ru纳米粒子的电子,减轻氧物种的过度吸收,并使持续的HOR催化成为可能.
结论:
- MnOx(OH) y修饰策略成功地抑制了Ru纳米颗粒上的氧物过度吸收,从而防止了活性衰变.
- 这种方法为设计下一代燃料电池所必需的强大的性HOR电催化剂提供了有希望的途径.
- 开发的催化剂在HEMFC中表现出卓越的性能,突出了其在实际能源转换应用中的潜力.
相关概念视频
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 Alkenes: Catalytic Hydrogenation
12.0K
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...
12.0K
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
Electrolysis
26.3K
In a galvanic cell, the electrical work is done by a redox system on its surroundings as electrons produced by the spontaneous redox reactions are transferred through an external circuit. Alternatively, an external circuit does work on a redox system by imposing a voltage sufficient to drive an otherwise nonspontaneous reaction in a process known as electrolysis. For instance, recharging a battery involves the use of an external power source to drive the spontaneous (discharge) cell reaction in...
26.3K
Catalysis
26.9K
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.
26.9K
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


