Two-step electrochemical intercalation and oxidation of graphite for the mass production of graphene oxide

Research output: Contribution to journalArticle

  • External authors:
  • Pei He
  • Mahdi Mohammed
  • Xin Zhao

Abstract

Conventional chemical oxidation routes for the production of graphene oxide (GO), such as the Hummers method, suffer from environmental and safety issues due to their use of hazardous and explosive chemicals. These issues are addressed by electrochemical oxidation methods but such approaches typically have a low yield due to inhomogeneous oxidation. Herein we report a two-step electrochemical intercalation and oxidation approach to produce GO on a large laboratory scale (ten’s of grams) comprising: (1) forming a stage 1 graphite intercalation compound (GIC) in concentrated sulfuric acid; (2) oxidizing and exfoliating the stage 1 GIC in an aqueous solution of 0.1 M ammonium sulfate. This two-step approach leads to GO with a high yield (>70 wt.%), good quality (>90%, monolayer), and reasonable oxygen content (17.7 at.%). Moreover, the as-produced GO can be subsequently deeply reduced (3.2 at.% oxygen; C/O ratio 30.2) to yield highly conductive (54,600 S m−1) reduced GO. Electrochemical capacitors based on the reduced GO showed an ultra-high rate capability of up to 10 V s−1 due to this high conductivity.

Bibliographical metadata

Original languageEnglish
Pages (from-to)17446-17456
Number of pages11
JournalAmerican Chemical Society. Journal
Volume139
Issue number48
Early online date1 Nov 2017
DOIs
Publication statusPublished - 2017