Fe-S dually modulated adsorbate evolution and lattice oxygen compatible mechanism for water oxidation.

Luo, Xu; Zhao, Hongyu; Tan, Xin; Lin, Sheng; Yu, Kesong; Mu, Xueqin; Tao, Zhenhua; Ji, Pengxia et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Simultaneously activating metal and lattice oxygen sites to construct a compatible multi-mechanism catalysis is expected for the oxygen evolution reaction (OER) by providing highly available active sites and mediate catalytic activity/stability, but significant challenges remain. Herein, Fe and S dually modulated NiFe oxyhydroxide (R-NiFeOOH@SO<sub>4</sub>) is conceived by complete reconstruction of NiMoO<sub>4</sub>·xH<sub>2</sub>O@Fe,S during OER, and achieves compatible adsorbate evolution mechanism and lattice oxygen oxidation mechanism with simultaneously optimized metal/oxygen sites, as substantiated by in situ spectroscopy/mass spectrometry and chemical probe. Further theoretical analyses reveal that Fe promotes the OER kinetics under adsorbate evolution mechanism, while S excites the lattice oxygen activity under lattice oxygen oxidation mechanism, featuring upshifted O 2p band centers, enlarged d-d Coulomb interaction, weakened metal-oxygen bond and optimized intermediate adsorption free energy. Benefiting from the compatible multi-mechanism, R-NiFeOOH@SO<sub>4</sub> only requires overpotentials of 251 ± 5/291 ± 1 mV to drive current densities of 100/500 mA cm<sup>-2</sup> in alkaline media, with robust stability for over 300 h. This work provides insights in understanding the OER mechanism to better design high-performance OER catalysts.