Xue Wendan, Zhou Qixing, Cui Xun, Zhang Jiawei, Zuo Sijin, Mo Fan, Jiang Jiwei, Zhu Xuya, Lin Zhiqun
Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Nankai University, Tianjin, 300071, P. R. China.
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
Angew Chem Int Ed Engl. 2023 Oct 9;62(41):e202307504. doi: 10.1002/anie.202307504. Epub 2023 Jul 12.
The past decade has witnessed the great potential of Fe-based single-atom electrocatalysis in catalyzing oxygen reduction reaction (ORR). However, it remains a grand challenge to substantially improve their intrinsic activity and long-term stability in acidic electrolytes. Herein, we report a facile chemical vapor deposition strategy, by which high-density Fe atoms (3.97 wt%) are coordinated with square-planar para-positioned nitrogen and phosphorus atoms in a hierarchical carbon framework. The as-crafted atomically dispersed Fe catalyst (denoted Fe-SA/PNC) manifests an outstanding activity towards ORR over the entire pH range. Specifically, the half-wave potential of 0.92 V, 0.83 V, and 0.86 V vs. reversible hydrogen electrode (RHE) are attained in alkaline, neutral, and acidic electrolytes, respectively, representing the high performance among reported catalysts to date. Furthermore, after 30,000 durability cycles, the Fe-SA/PNC remains to be stable with no visible performance decay when tested in 0.1 M KOH and 0.5 M H SO , and only a minor negative shift of 40 mV detected in 0.1 M HClO , significantly outperforming commercial Pt/C counterpart. The coordination motif of Fe-SA/PNC is validated by density functional theory (DFT) calculations. This work provides atomic-level insight into improving the activity and stability of non-noble metal ORR catalysts, opening up an avenue to craft the desired single-atom electrocatalysts.
在过去十年中，铁基单原子电催化在催化氧还原反应（ORR）方面展现出了巨大潜力。然而，要在酸性电解质中大幅提高其本征活性和长期稳定性，仍然是一个巨大的挑战。在此，我们报道了一种简便的化学气相沉积策略，通过该策略，高密度的铁原子（3.97 wt%）在分级碳框架中与平面正方形对位的氮和磷原子配位。所制备的原子分散铁催化剂（表示为Fe-SA/PNC）在整个pH范围内对ORR表现出优异的活性。具体而言，在碱性、中性和酸性电解质中，相对于可逆氢电极（RHE）的半波电位分别达到0.92 V、0.83 V和0.86 V，代表了迄今为止报道的催化剂中的高性能。此外，经过30000次耐久性循环后，在0.1 M KOH和0.5 M H₂SO₄中测试时，Fe-SA/PNC保持稳定，没有明显的性能衰减，而在0.1 M HClO₄中仅检测到40 mV的轻微负移，显著优于商业Pt/C催化剂。Fe-SA/PNC的配位模式通过密度泛函理论（DFT）计算得到验证。这项工作为提高非贵金属ORR催化剂的活性和稳定性提供了原子层面的见解，开辟了一条制备所需单原子电催化剂的途径。
