在氧电还原的铁--碳催化剂中使用二次金属的结构和反应效应
Fang Luo1, Aaron Roy2, Moulay Tahar Sougrati2
1Department of Chemistry, The Electrochemical Catalysis, Catalysis and Materials Science Laboratory, Chemical Engineering Division, Technical University Berlin, Straße des 17. Juni 124, 10623 Berlin, Germany.
Journal of the American Chemical Society
|June 28, 2023
概括
双金属铁-金属--碳 (FeMNC) 催化剂显示出增强的氧降解反应 (ORR) 活性. 将锡或添加到铁--碳 (FeNC) 催化剂中,通过优化特定的铁--碳活性位点,增加了循环频率.
科学领域:
- 材料科学
- 电化学
- 催化剂
背景情况:
- 双金属铁-金属--碳 (FeMNC) 催化剂对酸性介质中的氧降解反应 (ORR) 是有前途的.
- 了解FeMNC催化剂中的活性位点和金属相互作用对于优化其性能至关重要.
- 之前的研究表明活动有所改善, 但根本机制尚不清楚.
研究的目的:
- 阐明FeSnNC和FeCoNC催化剂中的活性位点和金属相互作用的性质.
- 将双金属FeMNC催化剂的结构和催化性能与单金属催化剂进行比较.
- 确定二次金属 (Sn,Co) 在增强ORR活动中的作用.
主要方法:
- 合成和描述FeSnNC,FeCoNC,FeNC和SnNC的催化剂.
- CO冷化学吸收以确定金属--碳 (M-Nx) 位点密度
- 电子显微镜和X射线吸收光谱用于结构分析.
- 铁Mössbauer光谱用于探测铁位点的局部环境.
主要成果:
- 双金属FeSnNC和FeCoNC催化剂的质量活性比FeNC催化剂高50-100%.
- 在双金属催化剂中,CO化学吸收显示出较低的M-Nx位密度,这表明转换频率增加.
- 光谱方法证实了Fe-Nx和Sn-Nx或Co-Nx位点的共存,没有证据表明Fe-M-Nx位点.
- 铁Mössbauer光谱显示了双金属催化剂的D1/D2比率增加,这表明D1Fe-Nx位点的比例更高.
结论:
- 将二次金属 (Sn,Co) 添加到FeNC催化剂中,通过增加活性站点的周转频率来增强ORR活动.
- 在二次金属添加时,D1 Fe-Nx位点的形成是催化性能改善的原因.
- 该研究澄清了FeMNC催化剂中的活性位点结构,区分了单个M-Nx位点,并排除了双核位点.
更多相关视频
08:40Synthesis of Metal Nanoparticles Supported on Carbon Nanotube with Doped Co and N Atoms and its Catalytic Applications in Hydrogen Production
Published on: December 6, 2021
3.6K
09:02Synthesis of Platinum-nickel Nanowires and Optimization for Oxygen Reduction Performance
Published on: April 27, 2018
7.8K
相关概念视频
02:51Metal-Ligand Bonds
21.1K
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
21.1K
02:34Structural Isomerism
19.5K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
19.5K
01:23Properties of Organometallic Compounds
1.1K
Organometallic compounds are compounds that contain a carbon–metal bond. Carbon belongs to an organyl group like alkyl, aryl, allyl, or benzyl groups. The metal can be from Group I or Group II of the periodic table, a transition metal, or a semimetal.
1.1K
03:45Formation of Complex Ions
23.8K
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
23.8K
02:58Crystal Field Theory - Octahedral Complexes
26.9K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
26.9K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.4K
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...
3.4K