Cu–N Dopants Boost Electron Transfer and Photooxidation Reactions of Carbon Dots

The broadband light-absorption ability of carbon dots (CDs) has inspired their application in photocatalysis, however this has been impeded by poor electron transfer inside the CDs. Herein, we report the preparation of Cu–N-doped CDs (Cu-CDs) and investigate both the doping-promoted electron transfer and the performance of the CDs in photooxidation reactions. The Cu–N doping was achieved through a one-step pyrolytic synthesis of CDs with Na2[Cu(EDTA)] as precursor. As confirmed by ESR, FTIR, and X-ray photoelectron spectroscopies, the Cu species chelates with the carbon matrix through Cu–N complexes. As a result of the Cu–N doping, the electron-accepting and -donating abilities were enhanced 2.5 and 1.5 times, and the electric conductivity was also increased to 171.8 μs cm−1. As a result of these enhanced properties, the photocatalytic efficiency of CDs in the photooxidation reaction of 1,4-dihydro-2,6-dimethylpyridine-3,5-dicarboxylate is improved 3.5-fold after CD doping.