Spin-state regulation of high-entropy Ruddlesden-Popper perovskite oxides for efficient seawater electrolysis.

Liu, Yifan; Hao, Libin; Ye, Caichao; Huang, Yin; Jin, Jing; Gong, Mingming; Chen, Long; Sun, Jingwen et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

High-entropy oxides have emerged as a promising group of candidates for various catalytic fields, including seawater electrolysis. However, without rational understanding and guidance, designing multielement compositions for high-entropy systems and elucidating the synergistic effect of diverse elements in catalysis remain significant challenges. Herein, we report spin-state regulation of a high-entropy Ruddlesden-Popper perovskite oxide for efficient seawater electrolysis. The Cu<sup>2+</sup> and Mn<sup>3+</sup> with Jahn-Teller effect induced a transition of Fe<sup>3+</sup>/Co<sup>3+</sup> spin state from low spin to high spin configuration. The high spin Fe<sup>3+</sup>/Co<sup>3+</sup> favor OH<sup>-</sup> adsorption and deprotonation during seawater oxidation. Besides, the oxygen intermediates adsorbed on high spin active sites repel the Cl<sup>-</sup> ions. Consequently, (La<sub>0.76</sub>Sr<sub>0.24</sub>)<sub>3</sub>(Fe<sub>0.22</sub>Co<sub>0.21</sub>Ni<sub>0.18</sub>Cu<sub>0.17</sub>Mn<sub>0.22</sub>)<sub>2</sub>O<sub>7</sub> achieved robust seawater oxidation for over 1200 h at 200 mA cm<sup>-2</sup>, showing competitive performance. The anion exchange membrane electrolyzer coupling with (La<sub>0.76</sub>Sr<sub>0.24</sub>)<sub>3</sub>(Fe<sub>0.22</sub>Co<sub>0.21</sub>Ni<sub>0.18</sub>Cu<sub>0.17</sub>Mn<sub>0.22</sub>)<sub>2</sub>O<sub>7</sub> anode and Pt/C cathode could maintain the seawater splitting performance of 1 A cm<sup>-2</sup> at 1.76 V and incessantly operate for 800 h. This spin-engineered strategy is universal to other high-entropy perovskite oxides and spinel oxides, offering promising way for designing efficient high-entropy catalysts.