S-Doped hierarchical graphene decorated with Co-porphyrins as an efficient electrocatalyst for zinc–air batteries. (13th August 2020)

• Record Type: Journal Article
• Authors: Peng, Zhi-Jie; Zhao, Jiao; Gu, Lei; Sun, Xuan-Long; Jia, Hai-Lang; Guan, Ming-Yun; Ma, Shuai-Shuai
• Is Part Of: New journal of chemistry. Volume 44:Number 34(2020)
• Page Start: 14343
• Page End: 14349
• Publication Date: 2020-08-13
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d0nj03443f
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : The ORR catalyst Por/S/rGO was prepared by S-doping and compositing with cobalt porphyrin, and the highly dispersed cobalt porphyrin greatly improved the catalytic performance. Abstract : The oxygen reduction reaction (ORR) is an important cathode reaction of fuel cells, metal–air batteries, water-splitting and other devices; however, the reaction kinetics is very slow, and thus the development of high-performance electrocatalysts has been one of the key research directions. In this work, we doped graphene with S element and the results of EDS mapping and XPS showed that the S-doping was successful. In addition, the doping process also faciltated graphene changing from the original chip to a thinner hierarchical structure. Combined with the macrocyclic porphyrin with rich Co–N4 active sites, the highly dispersed cobalt porphyrin greatly improved the catalytic performance. The high-performance ORR catalyst Por/S/rGO was prepared by S-doping and compositing with cobalt porphyrin, and was applied as a catalyst to the zinc–air battery. Electrochemical tests showed that Por/S/rGO had high ORR activity, which was comparable to commercial Pt/C. The onset potential and half-wave potential of Por/S/rGO were 0.91 and 0.812 V, respectively. Moreover, Por/S/rGO showed better long-term stability and methanol tolerance. Compared with a Pt/C-based Zn–air battery, the Por/S/rGO-based Zn–air battery displayed a higher galvanostatic discharge capacity as well as a desirable stability in 6 M KOH and 0.2 M Zn(OAc)2 alkaline electrolyte. The enhanced ORR activity of Por/S/rGO was attributed to the rich and highly dispersed Co-N4 active sites derived from the macrocyclic porphyrin and S-doping strategy.