Atomic-Layer IrO x Enabling Ligand Effect Boosts Water Oxidation Electrocatalysis

作者：Heng Luo, Fangxu Lin, Qinghua Zhang, Dawei Wang, Kai Wang, Lin Gu, Mingchuan Luo, Fan Lv, Shaojun Guo · 发表于：Journal of the American Chemical Society · 年份：2024 · DOI：10.1021/jacs.4c05165 · 被引用次数：73 · 研究领域：Electrocatalysts for Energy Conversion、Electrochemical Analysis and Applications、Fuel Cells and Related Materials

An in situ formed IrO x ( x ≤ 2) layer driven by anodic bias serves as the essential active site of Ir-based materials for oxygen evolution reaction (OER) electrocatalysis. Once being confined to atomic thickness, such an IrO x layer possesses both a favorable ligand effect and maximized active Ir sites with a lower O-coordination number. However, limited by a poor understanding of surface reconstruction dynamics, obtaining atomic layers of IrO x remains experimentally challenging. Herein, we report an idea of material design using intermetallic IrVMn nanoparticles to induce in situ formation of an ultrathin IrO x layer (O-IrVMn/IrO x ) to enable the ligand effect for achieving superior OER electrocatalysis. Theoretical calculations predict that a strong electronic interaction originating from an orderly atomic arrangement can effectively hamper the excessive leaching of transition metals, minimizing vacancies for oxygen coordination. Linear X-ray absorption near edge spectra analysis, extended X-ray absorption fine structure fitting outcomes, and X-ray photoelectron spectroscopy collectively confirm that Ir is present in lower oxidation states in O-IrVMn/IrO x due to the presence of unsaturated O-coordination. Consequently, the O-IrVMn/IrO x delivers excellent acidic OER performances with an overpotential of only 279 mV at 10 mA cm –2 and a high mass activity of 2.3 A mg –1 at 1.53 V (vs RHE), exceeding most Ir-based catalysts reported. Moreover, O-IrVMn/IrO x also showed ex...