Design of RuO2-CeO2 heterostructure for oxygen evolution reaction: Mitigating lattice oxygen mechanism-induced instability and enhancing catalytic performance

초록

This study focuses on developing an efficient anode catalyst for anion exchange membrane water electrolysis (AEMWE) based on ruthenium dioxide (RuO2), which suffers from particle agglomeration and lattice oxygen mechanism (LOM)-induced instability. To overcome these issues, ceria (CeO2) was incorporated to form a RuO2-CeO2 composite catalyst via a microemulsion route. X-ray diffraction analysis and transmission electron microscopy reveal a compact heterostructure arising from the lattice match between CeO2(111) and RuO2(110), while Brunauer-Emmett-Teller and double-layer capacitance analyses confirm increased surface area and exposure of Ru active sites. Density functional theory calculations reveal that oxygen vacancies preferentially form on the CeO2 domain (Delta E approximate to 1.8 eV per vacancy), indicating that CeO2 functions as an oxygen buffer that stabilizes the LOM-active RuO2 lattice. As a result, the RCO46 catalyst with an optimized ratio of RuO2 to CeO2 delivers a current density of 1.56 A cm- 2 at 2.0 V with a low degradation rate of 0.18 mA cm-2 h- 1 over 100 h in an AEMWE single cell, demonstrating a durable, high-performance OER catalyst with reduced Ru usage.

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