Arylamine-Linked Metallophthalocyanine Covalent Organic Polymers for Efficient Electrocatalytic Oxygen Reduction

Covalent organic polymers have emerged as promising platforms with tailorable structures for electrocatalytic oxygen reduction reaction (ORR). However, their catalytic activities are often limited by dense stacking and low conductivities. Herein, we report an arylamine-linked iron-phthalocyanine (AAm-FePc) in situ grown on Ketjenblack (KB) (AAm-FePc/KB) via a condensation reaction between 2,9,16,23-tetraaminophthalocyaninato iron and dimethyl succinyl succinate. Characterizations reveal that AAm-FePc is uniformly distributed on the surface of KB, which provides a large accessible surface area and efficient electrical conductivity. Owing to abundant arylamine linkages present in the skeletons and precisely designed highly active Fe–N4 sites, the AAm-FePc/KB catalyst exhibits excellent ORR characteristics in alkaline media, including a half-wave potential of 0.883 V, fast kinetics (Tafel slope = 33 mV dec–1), a nearly four-electron reduction pathway and excellent methanol resistance and electrochemical stability. The AAm-FePc/KB-catalyzed Zn–air battery exhibits a high power density (177.8 mW cm–2), a large specific capacity (727 mAh g–1), and outstanding cycling stability (375 cycles, 125 h), which are superior to those of commercial Pt/C catalyst.