Xue Dongping, Yuan Yifang, Yu Yue, Xu Siran, Wei Yifan, Zhang Jiaqi, Guo Haizhong, Shao Minhua, Zhang Jia-Nan
School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, China.
Key Laboratory of Materials Physics, Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou, 450052, China.
Nat Commun. 2024 Jul 16;15(1):5990. doi: 10.1038/s41467-024-50332-x.
Disentangling the limitations of O-O bond activation and OH* site-blocking effects on Pt sites is key to improving the intrinsic activity and stability of low-Pt catalysts for the oxygen reduction reaction (ORR). Herein, we integrate of PtFe alloy nanocrystals on a single-atom Fe-N-C substrate (PtFe@Fe-N-C) and further construct a ferromagnetic platform to investigate the regulation behavior of the spin occupancy state of the Pt d-orbital in the ORR. PtFe@Fe-N-C delivers a mass activity of 0.75 A mg at 0.9 V and a peak power density of 1240 mW cm in the fuel-cell, outperforming the commercial Pt/C catalyst, and a mass activity retention of 97%, with no noticeable current drop at 0.6 V for more than 220 h, is attained. Operando spectroelectrochemistry decodes the orbital interaction mechanism between the active center and reaction intermediates. The Pt dz orbital occupation state is regulated to te by spin-charge injection, suppressing the OH* site-blocking effect and effectively inhibiting HO production. This work provides valuable insights into designing high-performance and low-Pt catalysts via spintronics-level engineering.
厘清O-O键活化的局限性以及OH对铂位点的位阻效应，是提高用于氧还原反应（ORR）的低铂催化剂本征活性和稳定性的关键。在此，我们将铂铁合金纳米晶体集成在单原子铁氮碳基底（PtFe@Fe-N-C）上，并进一步构建一个铁磁平台，以研究ORR中铂d轨道自旋占据态的调控行为。PtFe@Fe-N-C在0.9 V时的质量活性为0.75 A mg，在燃料电池中的峰值功率密度为1240 mW cm，优于商业铂碳催化剂，并且实现了97%的质量活性保留率，在0.6 V下超过220小时无明显电流下降。原位光谱电化学解析了活性中心与反应中间体之间的轨道相互作用机制。通过自旋电荷注入将铂dz轨道占据态调控为te，抑制了OH位阻效应并有效抑制了HO的产生。这项工作为通过自旋电子学水平工程设计高性能低铂催化剂提供了有价值的见解。
