Skip to main content
. 2020 Jun 3;8:424. doi: 10.3389/fchem.2020.00424

Figure 5.

Figure 5

(A) Illustration of the preparation of GQDs by microwave-assisted chemical cleavage of GO sheets; reproduced from Li et al. (2012a) with permission from Wiley. (B) Microwave exfoliation of citric acid to fabricate GQDs; reproduced from Zhuang et al. (2016) with permission from Wiley. (C) Preparation of boron-doped GQDs (B-GQDs); reproduced from Hai et al. (2015) with permission from the Royal Society of Chemistry. (D) Preparation of nitrogen-doped GQDs (N-GQDs); reproduced from Ren et al. (2019) with permission from the American Chemical Society. (E) Ultrasonic preparation of GQDs using graphite; reproduced from Song et al. (2014) with permission from Wiley, and (F) coal as a precursor; reproduced from Zhang et al. (2019b) with permission from the American Chemical Society.