B‐Site‐Metal Exsolution on Perovskite Oxides Activates Alkaline Water Oxidation via the Lattice Oxygen Mechanism

Autor: Guangtai Han, Mengjiao Zhuansun, Tongbao Wang, Yuhang Wang
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Advanced Materials Interfaces, Vol 11, Iss 3, Pp n/a-n/a (2024)
Druh dokumentu: article
ISSN: 2196-7350
DOI: 10.1002/admi.202300760
Popis: Abstract Effective electrocatalysts are crucial for facilitating the oxygen evolution reaction (OER), the anodic reaction of water electrolysis for renewable green hydrogen production. Perovskite oxides are a group of potential catalysts featuring the lattice oxygen mechanism (LOM) for OER, where O2 formation commences via a lattice oxygen redox process. The LOM pathway breaks the thermodynamic limitation of the adsorbate evolution mechanism (AEM) and achieves a high intrinsic activity. However, perovskite oxides often suffer high OER overpotentials due to the insufficient activation of the LOM pathway. Typically, the overpotential exceeds 300 mV at 10 mA cm−2. This greatly impedes the practical applications of perovskite oxide based OER catalysts. Here, it is demonstrated that the B‐site‐metal exsolution of a La0.6Sr0.4Fe0.8Ni0.2O3‐δ perovskite increases the activity of LOM by a factor of 3.8 at 400 mV overpotential. The activated LOM pathway leads to a 36‐mV reduction in the overpotential at 10 mA cm−2 (from 310 mV to 274 mV) and a 2× increase in the turnover frequency (TOF) at 450 mV overpotential. A membrane electrode assembly (MEA) water electrolyzer equipped with this LSFN‐based catalyst offers 1 A cm−2 current density at 2.46 V and 24‐h operation stability.
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