Engineering Laboratory of Energy System Process Conversion and Emission Reduction Technology of Jiangsu Province, School of Energy and Mechanical Engineering, Nanjing Normal University, Nanjing 210023, China.
Engineering Laboratory of Energy System Process Conversion and Emission Reduction Technology of Jiangsu Province, School of Energy and Mechanical Engineering, Nanjing Normal University, Nanjing 210023, China.
Bioresour Technol. 2024 Dec;413:131490. doi: 10.1016/j.biortech.2024.131490. Epub 2024 Sep 15.
Biomass-derived carbon quantum dots (CQDs) have the advantage of being green and low-cost, but their complex structure makes the study of their formation mechanism encounter a bottleneck. Lignin-derived CQDs were prepared by a two-step process of "low-temperature liquid depolymerization" coupled with "hydrothermal reaction" in a mild organic acid system. In the first step of the low-temperature acidolysis process, the lignin polymer first undergoes deethering and depolymerization reactions. During the hydrothermal process in the second step, the organic small molecules on the surface of the supernatant are enriched with reactive groups that are dehydrated, condensed, crosslinked, and carbonized under high temperature and pressure to form CQDs. On the other hand, these activated large sp carbon domains in the oxidized solid residue from lignin acidolysis undergo hydrothermal cleavage under high-temperature and high-pressure conditions, followed by deoxygenation and eventual decomposition into small carbon domain CQDs products. Among them, the supernatant component C1 after lignin acidolysis with abundant N-H and C-OH reactive groups is targeted as a key precursor for the formation of lignin-derived CQDs, and the resulting CQDs have both the highest QY (19.5%) and yield (16.5%). This study bridges the research gap on the formation mechanism of biomass-derived CQDs and offers a reference for the sustainable preparation of biomass-derived CQDs.
生物质衍生的碳量子点（CQDs）具有绿色环保、成本低廉的优点，但由于其复杂的结构，其形成机制的研究遇到了瓶颈。本研究采用“低温液相解聚”与“在温和有机酸体系中的水热反应”两步法，制备了木质素衍生的 CQDs。在低温酸解过程的第一步中，木质素聚合物首先经历脱醚和解聚反应。在第二步的水热过程中，上清液表面的有机小分子被富含反应性基团的物质富集，这些反应性基团在高温高压下脱水、缩合、交联和碳化，形成 CQDs。另一方面，这些在木质素酸解产生的氧化固体残留物中被激活的大 sp 碳域在高温高压条件下发生水热断裂，然后脱氧并最终分解成小的碳域 CQDs 产物。其中，经过富含 N-H 和 C-OH 反应性基团的木质素酸解后的上清液组分 C1 被靶向作为木质素衍生 CQDs 形成的关键前体，所得到的 CQDs 具有最高的量子产率（19.5%）和产率（16.5%）。本研究弥合了生物质衍生 CQDs 形成机制研究的空白，为生物质衍生 CQDs 的可持续制备提供了参考。
