Journal
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
Volume 60, Issue 51, Pages 26829-26836Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/anie.202112447
Keywords
Aprotic Solvent; Cation Defect Evolution; NiFe-LDH; OER Electrocatalysis; Surface Reconstruction
Categories
Funding
- National Natural Science Foundation of China [22072124]
- National Natural Science Foundation of Fujian Province, China [2020J05016]
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The study shows that defects, specifically cationic vacancy defects, can enhance the electrocatalytic performance of NiFe-LDH for the oxygen evolution reaction (OER). These defects evolve with increasing applied voltage, influencing the surface reconstruction process of NiFe-LDH.
Defects have been found to enhance the electrocatalytic performance of NiFe-LDH for oxygen evolution reaction (OER). Nevertheless, their specific configuration and the role played in regulating the surface reconstruction of electrocatalysts remain ambiguous. Herein, cationic vacancy defects are generated via aprotic-solvent-solvation-induced leaking of metal cations from NiFe-LDH nanosheets. DFT calculation and in situ Raman spectroscopic observation both reveal that the as-generated cationic vacancy defects tend to exist as V-M (M=Ni/Fe); under increasing applied voltage, they tend to assume the configuration V-MOH, and eventually transform into VMOH-H which is the most active yet most difficult to form thermodynamically. Meanwhile, with increasing voltage the surface crystalline Ni(OH)(x) in the NiFe-LDH is gradually converted into disordered status; under sufficiently high voltage when oxygen bubbles start to evolve, local NiOOH species become appearing, which is the residual product from the formation of vacancy VMOH-H. Thus, we demonstrate that the cationic defects evolve along with increasing applied voltage (V-M -> V-MOH -> VMOH-H), and reveal the essential motif for the surface restructuration process of NiFe-LDH (crystalline Ni(OH)(x) -> disordered Ni(OH)(x) -> NiOOH). Our work provides insight into defect-induced surface restructuration behaviors of NiFe-LDH as a typical precatalyst for efficient OER electrocatalysis.
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