原子分散的 Zn-Co-N-C 催化剂通过稳定 Co-N 键来促进在酸中的高效和强大的氧降解催化
Feng Ma1,2, Xuan Liu1, Xiaoming Wang3
1State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
Fundamental research
|June 27, 2024
概括
添加 (Zn) 提高了过渡金属N-合碳 (M-N-C) 催化剂的稳定性,用于氧降解反应 (ORR). 这一突破为质子交换膜燃料电池 (PEMFC) 提供了耐用,无的替代品.
科学领域:
- 电化学 电化学 电化学
- 材料科学 材料科学 材料科学
- 催化剂是一种催化剂.
背景情况:
- 转变金属支持的N-化碳 (M-N-C) 催化剂是对组金属 (PGMs) 的有希望的替代品,用于质子交换膜燃料电池 (PEMFCs) 中的氧降解反应 (ORR).
- 在PEMFCs中发现的恶劣氧化条件下,M-N-C催化剂的稳定性是一个重大挑战,导致脱金属化和H2O2攻击等问题.
研究的目的:
- 研究 (Zn) 对提高ORR原子分散M-Nx/C (M = Co,Fe,Mn) 催化剂稳定性的普遍作用.
- 阐明Zn对这些催化剂的稳定作用背后的机制.
主要方法:
- 合成和特征的M-Nx/C催化剂与没有Zn.
- 电化学测试,包括半波电位 (E1/2) 测量和在酸性介质中的加速降解测试 (ADT).
- 进行X射线吸附光谱 (XAS) 和密度函数理论 (DFT) 计算,以分析催化剂结构,电子特性和结合.
主要成果:
- 双金属位点Zn-Co-N-C催化剂表现出0.81V与RHE的高半波潜力和卓越的耐用性,在60°C的15000个ADT周期后没有表现出活动衰变.
- 相比之下,没有的Co-N-C催化剂在ADT下由于脱金属化和更高的H2O2产量而迅速降解.
- XAS和DFT的计算显示,的结合导致了更负的形成能量 (1.2 eV的增加) 和Zn-Co双位结构中的增强的电荷转移,加强了Co-N键,并优化了d频段中心以改善ORR动力学.
结论:
- 普遍促进了ORR的原子分散的M-Nx/C催化剂的稳定性.
- Zn-Co-N-C催化剂在酸性介质中表现出卓越的性能和耐用性,超过了许多报告的无PGM催化剂.
- 增强的稳定性归因于加强的Co-N键和优化电子结构,这是由于Zn的结合而产生的.
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