Carbon particles are synthesized under hydrothermal conditions using different biomass (glucose, xylose, maltose, sucrose, amylopectin, starch) and biomass derivates (5-hydroxymethyl-furfural-1aldehyde-HMF-and furfural) as carbon sources. Carbons obtained from mono and polysaccharides, hexose and pentose sugars, and from the biomass derivatives, HMF and furfural, are compared from the particle morphology, chemical composition and structural point of view. A clear structural and morphological difference can be observed in carbons from pentoses and hexoses but in the last case, no matter the nature of the hexose sugar, all carbon materials showed astonishing similarities opening the way to the use of renewable biomass in the synthesis of such carbon materials.

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The local structure of carbon spheres obtained via the hydrothermal carbonization process is characterized by using a combination of advanced solid-state 13C NMR techniques. Glucose was chosen as the starting product because it offers the possibility of 13C isotopic enrichment and is regarded as a model compound for more complex polysaccharides and biomass, as reported in recent studies. A number of 13C solid-state MAS NMR techniques (single-pulse, cross-polarization, inversion recovery cross-polarization, INEPT, 13C−13C proton-driven magnetization exchange, and 13C−13C double-quantum−single-quantum correlation experiments) were combined to retrieve information about binding motifs and C−C closest neighbor relations. We found that the core of the carbonaceous scaffold is composed of furan rings cross-linked by domains containing short keto-aliphatic chains instead of otherwise expected graphene-type sheets, as mainly reported either for hydrothermal carbon spheres or for biomass-related carbons obtained by low-temperature (<350 °C) pyrolysis treatment.