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Confining High-Valence Iridium Single Sites onto Nickel Oxyhydroxide for Robust Oxygen Evolution
Nano Letters ( IF 9.6 ) Pub Date : 2022-04-22 , DOI: 10.1021/acs.nanolett.2c01124
Qun He 1 , Sicong Qiao 1 , Quan Zhou 1 , Yuzhu Zhou 1 , Hongwei Shou 1, 2 , Pengjun Zhang 1 , Wenjie Xu 1 , Daobin Liu 1 , Shuangming Chen 1 , Xiaojun Wu 2 , Li Song 1
Affiliation  

Enhancing activity and stability of iridium- (Ir-) based oxygen evolution reaction (OER) catalysts is of great significance in practice. Here, we report a vacancy-rich nickel hydroxide stabilized Ir single-atom catalyst (Ir1–Ni(OH)2), which achieves long-term OER stability over 260 h and much higher mass activity than commercial IrO2 in alkaline media. In situ X-ray absorption spectroscopy analysis certifies the obvious structure reconstruction of catalyst in OER. As a result, an active structure in which high-valence and peripheral oxygen ligands-rich Ir sites are confined onto the nickel oxyhydroxide surface is formed. In addition, the precise introduction of atomized Ir not only surmounts the large-range dissolution and agglomeration of Ir but also suppresses the dissolution of substrate in OER. Theoretical calculations further account for the activation of Ir single atoms and the promotion of oxygen generation by high-valence Ir, and they reveal that the deprotonation process of adsorbed OH is rate-determining.

中文翻译:

将高价铱单点限制在羟基氧化镍上以实现稳健的氧气释放

提高基于铱(Ir-)的析氧反应(OER)催化剂的活性和稳定性在实践中具有重要意义。在这里,我们报告了一种富含空位的氢氧化镍稳定的 Ir 单原子催化剂 (Ir 1 –Ni(OH) 2 ),它实现了超过 260 小时的长期 OER 稳定性和比商业 IrO 2高得多的质量活性。在碱性介质中。原位 X 射线吸收光谱分析证明了催化剂在 OER 中的明显结构重构。结果,形成了活性结构,其中富含高价和外围氧配体的Ir位点被限制在羟基氧化镍表面上。此外,雾化Ir的精确引入不仅克服了Ir的大范围溶解和团聚,而且抑制了底物在OER中的溶解。理论计算进一步解释了 Ir 单原子的活化和高价 Ir 促进氧的生成,它们揭示了吸附 OH 的去质子化过程是速率决定性的。
更新日期:2022-04-22
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