▎ 摘　　要

Much attention has been focused on the fabrication approaches of graphene quantum dots (GQDs) with efficient, time-saving, environmentally friendly and controllable approaches, which is well relevant to further applications. In this paper, we demonstrated the self-feedback autocatalysis progress in photosynthesis of N doped GQDs (N-GQDs). N-GQDs can be obtained via the simple ultraviolet (UV) irradiation for the mixture of urea, citric acid (CA) and H2O2. No by-product was generated during the preparation process and the yield of N-GQDs is 94 wt%. Compared with GQDs obtained via previously reported methods, the highly homogeneous size of these N-GQDs (2.4-3.1 nm) demonstrated the outstanding morphological control capacity of our suggested approach. More importantly, we demonstrated the self-feedback autocatalysis progress is the key factor for the suggested efficient preparation approach. Such self-feedback autocatalysis polymerization progress under ultraviolet irradiation is a rapid and effective method to obtain N-GQDs with good morphology and optical properties. This ultraviolet excitation-induced mechanism can be a universal method for numbers of nitrogen-containing precursors.