天津大学丁佳团队报道了伪酞菁配位环境下双原子铁的高效氧还原超过150000次循环。相关研究成果发表在2024年8月26日出版的《美国化学会杂志》。

原子分散的Fe-N-C催化剂成为商业Pt/C用于氧还原反应的有前景的替代品。然而，由于其较差的O-O键断裂能力和快速的铁脱金属，大多数Fe-N-C催化剂的活性和耐久性都不令人满意。

该文中，研究人员通过将酞菁铁（Fe-Nα-Cα-Nβ）的核心结构域接枝到缺陷碳上，创建了一种伪酞菁环境配位双原子铁（Fe₂-pPc）催化剂。原位表征和理论计算证实，Fe₂-pPc遵循快速动力学解离途径，从而引发桥型氧吸附并催化直接O-O自由基裂解。与传统的Fe-N-C和FePc基催化剂相比，Fe₂-pPc具有0.92 V的优越半波电位。

此外，pPc环境中超强的Nα-Cα键赋予双原子铁活性中心对反应诱导的几何应力的高耐受性，从而显著提高了对脱金属的抵抗力。在150000次前所未有的严酷加速降解试验中，Fe₂-pPc的铁损失可以忽略不计，活性衰减极小，仅为17 mV，是先前报道的Fe-N-C催化剂中最稳健的候选者。采用Fe₂-pPc的锌空气电池具有255 mW cm^-2的功率密度和440小时以上的出色运行稳定性。

该项工作为原子级精确金属催化剂的设计带来了新的见解。

附：英文原文

Title: Diatomic Iron with a Pseudo-Phthalocyanine Coordination Environment for Highly Efficient Oxygen Reduction over 150,000 Cycles

Author: Zechuan Huang, Mianfeng Li, Xinyi Yang, Tao Zhang, Xin Wang, Wanqing Song, Jinfeng Zhang, Haozhi Wang, Yanan Chen, Jia Ding, Wenbin Hu

Issue&Volume: August 26, 2024

Abstract: Atomically dispersed Fe–N–C catalysts emerged as promising alternatives to commercial Pt/C for the oxygen reduction reaction. However, the majority of Fe–N–C catalysts showed unsatisfactory activity and durability due to their inferior O–O bond-breaking capability and rapid Fe demetallization. Herein, we create a pseudo-phthalocyanine environment coordinated diatomic iron (Fe2-pPc) catalyst by grafting the core domain of iron phthalocyanine (Fe–Nα–Cα–Nβ) onto defective carbon. In situ characterizations and theoretical calculation confirm that Fe2-pPc follows the fast-kinetic dissociative pathway, whereby Fe2-pPc triggers bridge-mode oxygen adsorption and catalyzes direct O–O radical cleavage. Compared to traditional Fe–N–C and FePc-based catalysts exhibiting superoxo-like oxygen adsorption and an *OOH-involved pathway, Fe2-pPc delivers a superior half-wave potential of 0.92 V. Furthermore, the ultrastrong Nα–Cα bonds in the pPc environment endow the diatomic iron active center with high tolerance for reaction-induced geometric stress, leading to significantly promoted resistance to demetallization. Upon an unprecedented harsh accelerated degradation test of 150,000 cycles, Fe2-pPc experiences negligible Fe loss and an extremely small activity decay of 17 mV, being the most robust candidate among previously reported Fe–N–C catalysts. Zinc–air batteries employing Fe2-pPc exhibit a power density of 255 mW cm–2 and excellent operation stability beyond 440 h. This work brings new insights into the design of atomically precise metallic catalysts.

DOI: 10.1021/jacs.4c05111

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c05111