▎ 摘　　要

Carbon dots as a novel photocatalyst have attracted much attention, but they are still limited by their poor electron transfer properties. It is worth noting that graphene structures as a major component of carbon dots, play an important role in the electron transfer properties and photocatalysis. Herein, under different calcination temperature, carbon dots with various graphitization degrees were prepared from the mixture of EDTA-Fe and EDTA-Cu via a facile one-step pyrolysis. The graphitization degree of FeCu-CDs was proved by means of Raman, XRD and XPS spectra. The FeCu-CDs prepared at high temperature have higher graphitization degree and show excellent electron transfer ability. On the other hand, unsaturated metal dopants with mixed valence states (Fe2+, Fe3+, Cu+ and Cu2+) were fabricated and proved by XPS, ESR and FT-IR spectra, which are beneficial to further enhance both the electron donating/accepting abilities by changing their valence state. This higher graphitization degree and its synergy with dual metal dopants in FeCu-CDs can promote the photocatalytic efficiency in the photo-xidation reaction of 1,4-DHP. (c) 2017 Elsevier Ltd. All rights reserved.