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Updated: Aug 9, 2025
Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis
Published on: May 10, 2021
Evaluating Fe-Site and Vacancy Dependent Intrinsic Activity of NiFe Layered Double Hydroxides through Cavity
Duan Chen1, Ji Qiu1, Xing Chen1
1Key Laboratory of Theoretical Organic Chemistry and Functional Molecule, Ministry of Education, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201, China.
Abstract:
We report evaluating the intrinsic activity of Ni(OH)2, NiFe layered double hydroxides (LDHs), and NiFe-LDH having vacancies for oxygen evolution reaction (OER) by the use of cavity microelectrodes (CMEs) with controllable mass loading. The number of active Ni sites (NNi-sites) ranging from 1 × 1012 to 6 × 1012 is quantitatively correlated with OER current, which reveals that the introduction of Fe-sites and vacancies increases the turnover frequency (TOF) from 0.027 to 0.118 and 0.165 s-1, respectively. Electrochemical surface area (ECSA) is further quantitatively correlated with NNi-sites, which indicates that NNi-sites per unit ECSA (NNi-per-ECSA) is decreased by the introduction of Fe-sites and vacancies. Therefore, the difference of OER current per unit ECSA (JECSA) is reduced compared with that of TOF. The results demonstrate that CMEs provide a good platform to evaluate intrinsic activity with TOF, NNi-per-ECSA, and JECSA more reasonably.
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