Probing the catalytic activity of porous graphene oxide and the origin of this behaviour

• Published in: Nature communications Vol. 3; no. 1; p. 1298
• Main Authors: Su, Chenliang, Acik, Muge, Takai, Kazuyuki, Lu, Jiong, Hao, Si-jia, Zheng, Yi, Wu, Pingping, Bao, Qiaoliang, Enoki, Toshiaki, Chabal, Yves J., Ping Loh, Kian
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 2012; Nature Publishing Group
• Subjects: 639/638/298/918; 639/638/549; 639/638/77; Acids; Carbon; Catalysis; Chemistry; Graphene; Graphite; Humanities and Social Sciences; multidisciplinary; Oxidation; Precious metals; Science; Science (multidisciplinary); Singapore
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms2315

Graphene oxide, a two-dimensional aromatic scaffold decorated by oxygen-containing functional groups, possesses rich chemical properties and may present a green alternative to precious metal catalysts. Graphene oxide-based carbocatalysis has recently been demonstrated for aerobic oxidative reactions. However, its widespread application is hindered by the need for high catalyst loadings. Here we report a simple chemical treatment that can create and enlarge the defects in graphene oxide and impart on it enhanced catalytic activities for the oxidative coupling of amines to imines (up to 98% yield at 5 wt% catalyst loading, under solvent-free, open-air conditions). This study examines the origin of the enhanced catalytic activity, which can be linked to the synergistic effect of carboxylic acid groups and unpaired electrons at the edge defects. The discovery of a simple chemical processing step to synthesize highly active graphene oxide allows the premise of industrial-scale carbocatalysis to be explored.
Graphene oxide has been proposed as an alternative to precious metals for the catalysis of aerobic oxidative reactions; however, high catalyst loadings are needed. Here a simple base and acid treatment is shown to enhance its catalytic activity for the oxidative coupling of amines under ambient conditions.