Coordination modulation of iridium single-atom catalyst maximizing water oxidation activity

Zhanwu Lei,Xu Jin,Zhengxing Lv,Shuo Zhang,Kuan Wang,Wenhua Zhang,Jianming Li,Yang Liu,Shuhong Jiao,Wenbin Cai,Yifei Rao,Ruiguo Cao,Yuyuan Jiang,Pengfei Yan

doi:10.1038/s41467-021-27664-z

Abstract

Single-atom catalysts (SACs) have attracted tremendous research interests in various energy-related fields because of their high activity, selectivity and 100% atom utilization. However, it is still a challenge to enhance the intrinsic and specific activity of SACs. Herein, we present an approach to fabricate a high surface distribution density of iridium (Ir) SAC on nickel-iron sulfide nanosheet arrays substrate (Ir1/NFS), which delivers a high water oxidation activity. The Ir1/NFS catalyst offers a low overpotential of ~170 mV at a current density of 10 mA cm−2 and a high turnover frequency of 9.85 s−1 at an overpotential of 300 mV in 1.0 M KOH solution. At the same time, the Ir1/NFS catalyst exhibits a high stability performance, reaching a lifespan up to 350 hours at a current density of 100 mA cm−2. First-principles calculations reveal that the electronic structures of Ir atoms are significantly regulated by the sulfide substrate, endowing an energetically favorable reaction pathway. This work represents a promising strategy to fabricate high surface distribution density single-atom catalysts with high activity and durability for electrochemical water splitting.

Highlights

Single-atom catalysts (SACs) have attracted tremendous research interests in various energy-related fields because of their high activity, selectivity and 100% atom utilization
The oxygen evolution reaction (OER) reaction involves a four-electron process which suffers from ten times higher overpotentials than that of hydrogen evolution reaction (HER), making it a bottleneck process in the overall water electrolysis system[4,8]
The iridium precursor was added into the electrolyte and the electrode was swept between 0.3 V and −0.3 V versus Hg/HgO reference electrode for Ir single-atoms deposition

Summary

Introduction

Single-atom catalysts (SACs) have attracted tremendous research interests in various energy-related fields because of their high activity, selectivity and 100% atom utilization. Various substrate materials have been attempted to maximize the mass activity of previous metals[31,32,33,34,35] Despite these endeavors in developing suitable substrates for OER catalysts[17,36,37], the fundamental understanding of the interaction between the substrate and the supported isolated atoms is still illusive[38,39,40]. Another major challenge in the fundamental science of SACs is to enhance the surface distribution density of active sites on the outer surface of substrates, rather than embedded inside the bulk materials[28,38]

Methods

Results

Conclusion