Nanogold Empowered Energy: Oxygen Reduction and Oxygen Evolution Reactions Boost via Co Nanoclusters and NiFe-LDH Modulation

Abstract

Slow oxygen reduction and oxygen evolution reactions (ORR/OER) kinetics of rechargeable zinc air batteries (ZABs) severely constrain the practical deployment of ZABs. Here, a novel bifunctional catalyst, nanogold-modified NiFe-layered double hydroxides/Co nanocluster carbon nanoframes (Au-NiFe-LDH/Co-NC), is reported. This catalyst achieves a half-wave potential of 0.826 V and a Tafel slope of 79.1 mV dec−1, alongside outstanding OER activity, featuring a low overpotential of 300 mV at 10 mA cm−2 and a Tafel slope of 84.95 mV dec−1. Notably, its ΔE value (0.704 V) is lower than that of commercial catalysts (0.746 V), validating exceptional bifunctional activity. When integrated into ZABs, this catalyst delivers a peak power density of 169.0 mW cm−2, a specific capacity of 739.7 mAh g−1, and maintains robust cycling stability over 400 cycles with minimal charge/discharge voltage polarization. Electrochemical analysis, XPS analysis, and calculations demonstrate that Au nanoclusters modulate the electronic structure of Co and NiFe-LDH, enhancing ORR/OER activity by optimizing their d-band structures and reducing reaction overpotentials. This work offering significant potential for applications not only to ZABs but also to other catalytic reactions.