Structure of functionalized nitrogen-doped graphene hydrogels derived from isomers of phenylenediamine and graphene oxide based on their high electrochemical performance

• Published in: Electrochimica acta 2016-09, Vol.212, p.828-838
• Main Authors: Zou, Yubo, Zhong, Wenbin, Li, Shichao, Luo, Jinwei, Xiong, Changlun, Yang, Wantai
• Format: Article
• Language: English
• Subjects: functionalized; N-doped graphene hydrogels; phenylenediamine isomers; structure; supercapacitor
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2016.07.054

[Display omitted] •Functionalized N-doped graphene hydrogels (FONGH, FMNGH and FPNGH) are prepared from GO and isomers of phenylenediamine.•The different microstructures of FONGH, FMNGH and FPNGH are analyzed.•FONGH, FMNGH and FPNGH exhibit excellent electrochemical performance. Three functionalized N-doped graphene hydrogels were prepared from graphene oxide (GO) and isomers of phenylenediamine through hydrothermal process, which were (1) FONGH prepared with o-phenylenediamine (OPD); (2) FMNGH prepared with m-phenylenediamine (MPD) and (3) FPNGH prepared with p-phenylenediamine (PPD). As-prepared FONGH, FMNGH and FPNGH possessed different microstructures and exhibited different specific surface area: 107.8, 24.3 and 145.2m2g−1. The prepared graphene hydrogels were found with different N contents: FONGH (11.1 at.%)>FPNGH (9.8 at.%)>FMNGH (7.2 at.%). High resolution N 1s spectra of as-prepared hydrogels revealed that OPD facilitated the preparation of graphene with high doping level of nitrogen; while PPD was favorable to preparing N-doped graphene hydrogel with high moieties of amine including -NH2 or N covalent bonded with sp3-C of graphene. As-prepared FONGH, FMNGH and FPNGH exhibited excellent electrochemical performance with high specific capacitance (645, 365.7 and 467Fg−1 at 1Ag−1) and superior cycling stability (97.6%, 83.1% and 91% retention at 20Ag−1 after 1000 cycles). The different microstructures and electrochemical performance of FONGH, FMNGH and FPNGH were caused by different positions of -NH2 groups on the benzene rings of OPD, MPD and PPD. The present work proposes a novel idea to prepare functionalized N-doped graphene with high electrochemical performance.