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

Lei, Zhanwu; Cai, Wenbin; Rao, Yifei; Wang, Kuan; Jiang, Yuyuan; Liu, Yang; Jin, Xu; Li, Jianming et al. · Nat Commun · 2022

basic_science · Level V

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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 (Ir<sub>1</sub>/NFS), which delivers a high water oxidation activity. The Ir<sub>1</sub>/NFS catalyst offers a low overpotential of ~170 mV at a current density of 10 mA cm<sup>-2</sup> and a high turnover frequency of 9.85 s<sup>-1</sup> at an overpotential of 300 mV in 1.0 M KOH solution. At the same time, the Ir<sub>1</sub>/NFS catalyst exhibits a high stability performance, reaching a lifespan up to 350 hours at a current density of 100 mA cm<sup>-2</sup>. 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.