Chen Xiaoxia, Liu Meihuan, Ni Chudi, Chen Yiwen, Liu Tianwen, Li Shiyu, Su Hui
Key Laboratory of Light Energy Conversion Materials of Hunan Province College, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, China.
State Key Laboratory for Powder Metallurgy, Central South University, Changsha, Hunan, 410083, China.
Small. 2025 Jan;21(4):e2409173. doi: 10.1002/smll.202409173. Epub 2024 Dec 1.
Ruthenium (Ru)-based catalysts have emerged as promising alternatives to Iridium (Ir) catalysts in proton exchange membrane water electrolysis cells due to their lower price and excellent oxygen evolution reaction (OER) activity. However, their stability is compromised by generation of unstable high-valence Ru sites and oxygen vacancy in a lattice oxygen-mediated (LOM) pathway. Here, a low-load Ru site on a Barium (Ba)-doped CoO (RuBaCoO) catalyst is developed with abundant Ruthenium─Cobalt (Ru─Co) pairs for enhanced acidic OER activity. The incorporation of Ba can efficiently modulate the lattice of CoO, creating Ru─Co active pairs with optimized spacing through compression stress. In situ characterizations exhibit contractive Ru─Co pairs that promote the rapid and direct coupling of O─O radicals, bypassing the sluggish OOH species and avoiding the oxygen vacancies, which can trigger the oxide path mechanism (OPM) for an efficient and stable OER process. As a result, the designed catalyst delivers a low overpotential of 219 mV to achieve a current density of 10 mA cm, and also demonstrates excellent stability, maintaining performance over 50 h of continuous operation at a larger current density of 50 mA cm. These findings highlight the potential of the RuBaCoO catalysts for durable and efficient OER applications.
钌（Ru）基催化剂因其价格较低且具有优异的析氧反应（OER）活性，已成为质子交换膜水电解槽中铱（Ir）催化剂的有前景的替代物。然而，它们的稳定性因在晶格氧介导（LOM）途径中产生不稳定的高价Ru位点和氧空位而受到损害。在此，开发了一种负载量低的钡（Ba）掺杂氧化钴（RuBaCoO）催化剂上的Ru位点，其具有丰富的钌 - 钴（Ru - Co）对，以增强酸性OER活性。Ba的掺入可以有效地调节CoO的晶格，通过压缩应力产生具有优化间距的Ru - Co活性对。原位表征显示收缩的Ru - Co对，其促进O - O自由基的快速直接耦合，绕过缓慢的OOH物种并避免氧空位，这可以触发氧化物路径机制（OPM）以实现高效稳定的OER过程。结果表明，所设计的催化剂在电流密度为10 mA cm时具有219 mV的低过电位，并且还表现出优异的稳定性，在50 mA cm的更大电流密度下连续运行超过50小时仍保持性能。这些发现突出了RuBaCoO催化剂在耐用和高效OER应用中的潜力。
