Vaporized-salt-induced sp3-hybridized defects on nitrogen-doped carbon surface towards oxygen reduction reaction. (15th August 2021)

• Record Type: Journal Article
• Authors: Cao, Yuanjie; Liu, Zhang; Tang, Yuanting; Huang, Chaojun; Wang, Zhili; Liu, Feng; Wen, Yanwei; Shan, Bin; Chen, Rong
• Is Part Of: Carbon. Volume 180(2021)
• Page Start: 1
• Page End: 9
• Publication Date: 2021-08-15
• Subjects: Vaporized salt -- sp3 hybridized defects -- Metal-free -- Oxygen reduction reaction; Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2021.04.059
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: The intrinsic carbon defects including pentagons, vacancies and sp 3 -hybridized carbon have recently been proposed as efficient reactive sites for oxygen reduction reaction (ORR). Nevertheless, it is still a great challenge to controllably introduce the intrinsic defects into carbon materials. Herein, a universal defect-engineering method via vaporized salt is reported to modify the N-doped carbon surface with abundant sp 3 -hybridized carbon defects. At an elevated temperature, the vaporized sodium chloride is found to selectively modulate the surface structure of carbon material. The obtained carbon-based electrocatalyst delivers an outstanding electrocatalytic ORR property with a half-wave potential ( E 1/2 ) of 0.85 V vs . RHE and an excellent performance in zinc air battery (ZAB) test. The analysis of components and structures of surface elements via XANES and XPS reveals that the increasing sp 3 -hybridized carbon defects, induced by the vaporized-salt modification, are responsible for the enhancement of ORR performance. The theoretical calculations further suggest the sp 3 component hybridizes with original sp 2 carbon, forming efficient sp 2 /sp 3 hybridized carbon sites towards ORR. Additionally, other halide salts are proved to have the similar effect on promoting ORR activity and this method can expand to other carbon-based materials, suggesting its universality and significance in synthesis of defect-rich carbon-based materials. Graphical abstract: Image 1 Highlights: A universal defect-engineering method via vaporized salt halide was developed. The vaporized-salt-treated catalysts exhibited a superior ORR activity. XANES, XPS, Raman and DFT calculations were applied to reveal the active sites. The raised ORR activity was induced by the increasing sp 3 carbon defects.