Fig. 1. (a) A diverse set of locally sourced renewable precursors can be used for the green synthesis of CDs. A reference list of these images can be found in Table S1 of the ESI.† (b) Sankey diagram showing the number of green-synthesized CD publications reporting various pathways from carbon source to CD. For this diagram, it is assumed that the purification steps followed the order: (1) filtration, (2) centrifugation, (3) dialysis, although this was not always the case, and this assumption was made for illustrative purposes only. A hybrid precursor indicates that both a renewable raw material and renewable refined compound were used. The most common synthesis route uses a renewable raw material in a hydrothermal synthesis followed by one or more purification steps. A reference list can be found in Table S2 of the ESI.†.