A previous study reported that graphene quantum dots (GQDs) generated by electrooxidation of graphene had a uniform size of 3-5 nm and exhibit excitation wavelength-dependent photoluminescence (PL). Here, larger GQDs with an average diameter of ca. 52 nm are obtained via using similar method. And their PL show excitation wavelength-independent properties. (C) 2017 Elsevier B.V. All rights reserved.