Discharge‐Induced Enhancement of the Oxygen Evolution Reaction. Issue 36 (6th August 2021)

• Record Type: Journal Article
• Authors: Hao, Jinhui; Luo, Wei; Wang, Shuaishuai; Zhao, Kun; Hou, Jianwen; Li, Longhua; Ge, Baoxin; Yang, Wenshu; Shi, Weidong
• Is Part Of: Angewandte Chemie international edition. Volume 60:Issue 36(2021)
• Page Start: 20042
• Page End: 20048
• Publication Date: 2021-08-06
• Subjects: discharge -- doping -- electrochemistry -- oxygen evolution reaction -- vacancy; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202108770
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The fundamental understanding of the surface reconstruction induced by the applied potential is of great significance for enhancing the oxygen evolution reaction (OER). Here, we show that a previously overlooked discharge current in the low applied potential region also leads to in situ electrochemical activation of a nitrogen‐doped nickel oxyhydroxide surface. We exploit the fact that doping of heteroatoms weakens the surface structure, and hence, a weak discharge current originating from the capacitive nature of nickel oxyhydroxide has a strong structure‐reforming ability to promote the formation of nitrogen and oxygen vacancies. The current density at 1.4 V (vs. Hg/HgO) can dramatically increase by as much as 31.3 % after discharge in the low applied potential region. This work provides insight into in situ enhancement of the OER and suggests that the low applied potential region must be a primary consideration in evaluating the origin of the activity of electrocatalysts. Abstract : Current mechanism studies mainly concern surface reconstruction at high potential with respect to formation of high‐valence metal sites and metal oxyhydroxides. The understanding of correlation between low potential scanning, surface structure, and electrochemical activity is lacking. This work suggests that the low applied potential region must be a primary consideration in evaluating the origin of the activity of electrocatalysts.