催化作用
化学
氧气
吸附
酞菁
双原子分子
金属
键裂
光化学
物理化学
分子
有机化学
作者
Zechuan Huang,M. Li,Xinyi Yang,Tao Zhang,Jia Li,Wanqing Song,Jinfeng Zhang,Haozhi Wang,Yanan Chen,Jia Ding,Wenbin Hu
摘要
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.
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