Iron phthalocyanine coupled with Co-Nx sites in carbon nanostraws for Zn-Air batteries
Yi Wu, Junliang Chen, Jie Liu, Linjie Zhang, Reza Abazari, Tingting Li, Jinjie Qian
Abstract
The energy crisis heightens interest in proton exchange membrane fuel cells (PEMFCs), where the oxygen reduction reaction (ORR) is a critical cathodic process hindered by its intrinsic sluggish kinetics. Single-atom catalysts (SACs) at the molecular level, notably those featuring an Fe-N 4 structure derived from iron phthalocyanine (FePc), exhibit significant potential but confront the challenges of aggregation and inadequate electrical conductivity. Herein, we present a novel FePc coupled with defect-rich CoN x -doped hollow carbon nanostraw derived from cobalt-doped indium-based metal–organic frameworks (MOFs). This enhancement is attributed to the CoN x structure’s effective modulation of the Fe-N 4 active sites, further complemented by the hollow nanostraw structure, which significantly increases the accessibility of active sites, thereby promoting enhanced catalytic performance. FePc@HCoNC demonstrates exceptional ORR performance with an oxygen reduction potential of 0.903 V, half-wave potential of 0.914 V, and limiting current density of 5.18 mA cm −2 . For zinc-air batteries (ZABs), FePc@HCoNC achieves an open-circuit voltage of 1.524 V, peak power density of 153.06 mW cm −2 , specific capacity of 758.10 mAh g −1 , and stable cycling for 150 h. These findings underscore its potential as a superior alternative to precious metal-based catalysts, offering a pathway to more sustainable and efficient energy conversion technologies.