▎ 摘　　要

An advanced simple synthetic route for graphene quantum dots (GQDs) is great importance to progress from laboratory research to industrial applications. Unfortunately, the existing state of synthesis methods of carboxylic acid-rich GQDs needs additional reaction steps including oxidation, hydro- or solvo-thermal reaction with bulk carbon sources. Besides, its yield is too low compared to starting amount of carbon sources due to complicated purification processes. Hence, production expense is inevitably increased to obstacle actual industrial applications. Here, we report a new synthetic method based on the liquid-phase extraction technique to separate carboxylate-rich GQDs (CGQDs) with high yield (> 30%) from graphene oxide (GO) dispersions without additional oxidation and purification processes.