Fig. 3: Benzene polycarboxylic acids (BPCAs) compositions of polycyclic aromatics in the Chang’E 5 lunar soils and terrestrial analogs (i.e., kerogen, wood char and soot).
The results for natural kerogen are presented in (A), while those for the artificial thermal series of kerogen and wood char, as well as soot, are shown in (B). The y-axis represents the percentage of individual BPCAs relative to the total BPCAs in carbon content. The BPCAs substituted with two carboxylic groups (B2CAs) were excluded from the calculation, consistent with previous studies, to enable direct comparison21,74. Errors for samples other than the lunar soils are not shown, as they are less than 2%. The “*” in the labels on the x-axis denotes data from the literatures21,74, while other results are from this study (see Supplementary Methods, Table S4–6). The result of graphene sheet composed of a 10 × 10 benzene-ring array (#24) is based on theoretical calculations (see Supplementary Method, Table S7). The maturity of natural type I and II kerogen was determined using vitrinite reflectance (Table S4). The maturity of natural type III kerogen was determined based on volatile matter content on a dry ash-free basis (Table S5).
