Towards an enhanced nanocarbon crystallization from lignin

In this work, a new approach to the synthesis of lignin-derived nanocarbon crystals based on lignin depoly-merization is proposed. The lignin chemical structure was modified through a controlled routine, which was based on sequential UV light irradiation, hydrothermal carbonization in autoclave, vacuum degassing, pyrolysis and mechanical exfoliation. In this way, we were able to obtain a lignin-based nanocarbon with a sp2-hybridized nanoporous framework structure with oxygenated functional groups attached to this structure. The used catalyst -free route resulted in high nanocarbon yields and turns out to be an eco-friendly strategy of a synthesis of low-cost carbon materials. The characterization of the lignin-derived nanocarbon was carried out using X-ray diffraction measurements, infrared, Raman and X-ray photoelectrons spectroscopies analyses. The nanocarbon materials' morphology was evaluated by scanning and transmission electron microscopy. The method of lignin's transformation developed in this work showed itself as a promising alternative for provision of large amounts of carbon-based materials for industrial applications. The proposed approach may be adapted to various biomass feedstocks with aromatic groups' content suitable for their high yield polycondensation. The achieved nano -carbon yield, when starting from a commercial purified lignin, varied between 50 wt% and 70 wt%.

Automated summary

A new approach to synthesize lignin-derived nanocarbon crystals based on lignin depolymerization is proposed in this study. The chemical structure of lignin was modified using a controlled routine involving UV light irradiation, hydrothermal carbonization, vacuum degassing, pyrolysis, and mechanical exfoliation. This method resulted in a lignin-based nanocarbon with a nanoporous framework structure and oxygenated functional groups. The catalyst-free route used in this study showed high nanocarbon yields and is an eco-friendly strategy for synthesizing low-cost carbon materials. The characterization of the lignin-derived nanocarbon included X-ray diffraction, infrared, Raman, and X-ray photoelectron spectroscopies, as well as scanning and transmission electron microscopy. The developed transformation method has the potential to provide large amounts of carbon-based materials for industrial applications, and it can be adapted to various biomass feedstocks with suitable aromatic groups for high yield polycondensation. The achieved nano-carbon yield ranged from 50 wt% to 70 wt% when starting from a commercial purified lignin.