▎ 摘　　要

S,N co-doped graphene quantum dots (S, N-GQDs) were successfully combined with graphitic carbon nitride (g-C3N4) in a facile manner by a physical method. The as-prepared g-C3N4/S,N:GQD composites were characterized by X-ray diffraction, high-resolution field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, diffuse-reflectance spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, and other techniques. The g-C3N4/S,N:GQD composites exhibit higher photocatalytic performance for degrading Rhodamine B (RhB) under visible-light irradiation than the pure g-C3N4. The enhancement of photodegradation activity is attributed to the efficient separation of photogenerated electrons and holes. Moreover, these composites can be reused for the degradation of RhB during nine cycles, without a significant decrease in the photocatalytic activity. Finally, a possible charge separation mechanism was proposed. (C) 2016 Elsevier B.V. All rights reserved.