Li Xiaoning, Liu Huan, Sun Yanhua, Zhu Liuyang, Yin Xiaofeng, Sun Shujie, Fu Zhengping, Lu Yalin, Wang Xiaolin, Cheng Zhenxiang
Institute for Superconducting & Electronic Materials (ISEM) Australia Institute for Innovative Materials Innovation Campus University of Wollongong Squires Way North Wollongong NSW 2500 Australia.
Department of Materials Science and Engineering University of Science and Technology of China Hefei 230026 P. R. China.
Adv Sci (Weinh). 2020 Sep 29;7(22):2002242. doi: 10.1002/advs.202002242. eCollection 2020 Nov.
The participation of lattice oxygen in the oxygen evolution reaction (OER) process has been proved to be faster in kinetics than the mechanisms where only metal is involved, although activating the lattice oxygen in the traditional rigid structures remains a big challenge. In this work, efforts are devoted to exploring a new flexible structure that is competent in providing large amounts of oxygen vacancies as well as offering the freedom to manipulate the electronic structure of metal cations. This is demonstrated by anchoring low valence state Co at high valence state Nb sites in the tetragonal tungsten bronze (TTB)-structured SrBaNb Co O , with different ratios of Co to Nb to optimize the Co substitution proportion. It is found that the occupation of Co in the Nb sites gives rise to the generation of massive surface oxygen vacancies (O), while Co itself is stabilized in Co by adjacent O. The coexistence of O and LS Co enables an oxygen intercalation mechanism in the optimal SBNC45 with specific activity at 1.7 V versus reversible hydrogen electrode that is 20 times higher than for the commercial IrO. This work illuminates an entirely new avenue to rationally design OER electrocatalysts with ultrafast kinetics.
晶格氧参与析氧反应（OER）过程的动力学已被证明比仅涉及金属的机制更快，尽管在传统刚性结构中激活晶格氧仍然是一个巨大的挑战。在这项工作中，致力于探索一种新的柔性结构，该结构能够提供大量氧空位，并能自由操纵金属阳离子的电子结构。这通过将低价态的Co锚定在四方钨青铜（TTB）结构的SrBaNb Co O中的高价态Nb位点上得以证明，通过改变Co与Nb的比例来优化Co的取代比例。研究发现，Co占据Nb位点会导致大量表面氧空位（O）的产生，而Co本身通过相邻的O稳定在Co 中。O和低价态Co的共存使得在最优的SBNC45中存在一种氧嵌入机制，其相对于可逆氢电极在1.7 V时的比活性比商业IrO 高20倍。这项工作为合理设计具有超快动力学的OER电催化剂开辟了一条全新的途径。
