Graphene oxide, a two dimensional aromatic scaffold decorated by oxygen functional groups, possesses rich chemical properties and presents a green alternative to precious metal catalysts. Graphene oxide based carbocatalysis has recently been demonstrated in aerobic oxidative reactions. However its widespread application is hindered by high catalyst loading. Here we report a simple chemical treatment that can create and enlarge the defects in graphene oxide and impart on it enhanced catalytic activities in the oxidative coupling of amines to imines (up to 98% yield and 5 wt. % catalyst loading under solvent-free, open-air condition). 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.
Nature Communications (DOI: 10.1038/ncomms2315).
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