Spatial, well-defined metal-corrole-based covalent organic polymers for remarkably enhanced multipurpose electrocatalysis and high-performance zinc–air batteries

Abstract

Incorporating the intrinsic catalytic activity of discrete molecular catalysts into covalent frameworks often enables improved electrocatalytic performance. Metallocorroles that represent a burgeoning class of attractive metal-complexes, from the porphyrinoid family, are significantly promising molecular catalysts for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). However, their low catalytic current density and poor stability are undesirable for practical applications. Heterogenizing metal corroles can potentially address these issues, and the resulting integrated catalysts greatly improve the electrocatalytic performance by efficiently avoiding the agglomeration of metallocorroles, but this process is challenging. Herein, a class of spatial, well-defined metal-corrole-based covalent organic polymers (COPs) were prepared and their electrocatalytic ORR, OER, and HER activities in 0.1 M KOH solution were studied. Compared with metallocorroles, M-COPs (M = H, Co, Fe, and Cu) showed obviously enhanced catalytic activity and stability. The Co-COP as a trifunctional electrocatalyst outperformed other M-COPs with a high half-wave potential of 0.80 V for ORR and a low overpotential for OER (560 mV) and HER (208 mV) at 10 mA cm⁻². The Co-COP catalyst was utilized to assemble a rechargeable Zn–air battery that exhibited high specific capacity (734 mA h g⁻¹) and power density (83.5 mW cm⁻²). This work is unparalleled in the development and exploration of metal-corrole-based COPs as multipurpose electrocatalysts.