Xue Yanrong, Zhao Jiwu, Huang Liang, Lu Ying-Rui, Malek Abdul, Gao Ge, Zhuang Zhongbin, Wang Dingsheng, Yavuz Cafer T, Lu Xu
CCRC, Division of Physical Science and Engineering (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
KAUST Solar Center (KSC), PSE, KAUST, Thuwal, Kingdom of Saudi Arabia.
Nat Commun. 2023 Dec 7;14(1):8093. doi: 10.1038/s41467-023-43977-7.
Ruthenium dioxide is the most promising alternative to the prevailing but expensive iridium-based catalysts for the oxygen evolution reaction in proton-exchange membrane water electrolyzers. However, the under-coordinated lattice oxygen of ruthenium dioxide is prone to over-oxidation, and oxygen vacancies are formed at high oxidation potentials under acidic corrosive conditions. Consequently, ruthenium atoms adjacent to oxygen vacancies are oxidized into soluble high-valence derivatives, causing the collapse of the ruthenium dioxide crystal structure and leading to its poor stability. Here, we report an oxyanion protection strategy to prevent the formation of oxygen vacancies on the ruthenium dioxide surface by forming coordination-saturated lattice oxygen. Combining density functional theory calculations, electrochemical measurements, and a suite of operando spectroscopies, we showcase that barium-anchored sulfate can greatly impede ruthenium loss and extend the lifetime of ruthenium-based catalysts during acidic oxygen evolution, while maintaining the activity. This work paves a new way for designing stable and active anode catalysts toward acidic water splitting.
二氧化钌是质子交换膜水电解槽中用于析氧反应的最有前景的替代催化剂，可替代目前使用但价格昂贵的铱基催化剂。然而，二氧化钌中配位不足的晶格氧易于过度氧化，并且在酸性腐蚀条件下，在高氧化电位下会形成氧空位。因此，与氧空位相邻的钌原子被氧化成可溶性高价衍生物，导致二氧化钌晶体结构崩溃并使其稳定性变差。在此，我们报道了一种氧阴离子保护策略，通过形成配位饱和的晶格氧来防止二氧化钌表面形成氧空位。结合密度泛函理论计算、电化学测量和一系列原位光谱技术，我们证明钡锚定的硫酸盐可以极大地阻碍钌的损失，并在酸性析氧过程中延长钌基催化剂的寿命，同时保持活性。这项工作为设计用于酸性水分解的稳定且活性高的阳极催化剂开辟了一条新途径。
