Dynamic chloride ion adsorption on single iridium atom boosts seawater oxidation catalysis.

Duan, Xinxuan; Sha, Qihao; Li, Pengsong; Li, Tianshui; Yang, Guotao; Liu, Wei; Yu, Ende; Zhou, Daojin et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Seawater electrolysis offers a renewable, scalable, and economic means for green hydrogen production. However, anode corrosion by Cl<sup>-</sup> pose great challenges for its commercialization. Herein, different from conventional catalysts designed to repel Cl<sup>-</sup> adsorption, we develop an atomic Ir catalyst on cobalt iron layered double hydroxide (Ir/CoFe-LDH) to tailor Cl<sup>-</sup> adsorption and modulate the electronic structure of the Ir active center, thereby establishing a unique Ir-OH/Cl coordination for alkaline seawater electrolysis. Operando characterizations and theoretical calculations unveil the pivotal role of this coordination state to lower OER activation energy by a factor of 1.93. The Ir/CoFe-LDH exhibits a remarkable oxygen evolution reaction activity (202 mV overpotential and TOF = 7.46 O<sub>2</sub> s<sup>-1</sup>) in 6 M NaOH+2.8 M NaCl, superior over Cl<sup>-</sup>-free 6 M NaOH electrolyte (236 mV overpotential and TOF = 1.05 O<sub>2</sub> s<sup>-1</sup>), with 100% catalytic selectivity and stability at high current densities (400-800 mA cm<sup>-2</sup>) for more than 1,000 h.