Molecular Engineering of a 3D Self-Supported Electrode for Oxygen Electrocatalysis in Neutral Media.

Electrodes for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are required in energy conversion and storage technologies. An assembly strategy involves covalently grafting Co corrole 1 onto Fe3 O4 nanoarrays grown on Ti mesh. The resulted electrode shows significantly improved activity and durability for OER and ORR in neutral media as compared to Fe3 O4 alone and with directly adsorbed 1. It also displays higher atom efficiency (at least two magnitudes larger turnover frequency) than reported electrodes. Using this electrode in a neutral Zn-air battery, a small charge-discharge voltage gap of 1.19 V, large peak power density of 90.4 mW cm-2 , and high rechargeable stability for >100 h are achieved, opening a promising avenue of molecular electrocatalysis in a metal-air battery. This work shows a molecule-engineered electrode for electrocatalysis and demonstrates their potential applications in energy conversion and storage.