Fernandes Sónia, Algarra Manuel, Gil Antonio, Esteves da Silva Joaquim, Pinto da Silva Luís
Chemistry Research Unit (CIQUP), Department of Geosciences, Environment and Spatial Plannings, Faculty of Sciences, Institute of Molecular Sciences (IMS), University of Porto, R. Campo Alegre s/n, Porto, 4169-007, Portugal.
Department of Science, Public University of Navarre INAMAT - Institute for Advanced Materials and Mathematics, Campus of Arrosadia, 31006, Pamplona, Spain.
ChemSusChem. 2025 Jan 14;18(2):e202401702. doi: 10.1002/cssc.202401702. Epub 2024 Dec 4.
Carbon dots (CDs) are fluorescent carbon-based nanomaterials with remarkable properties, making them more attractive than traditional fluorophores. Consequently, researchers focused on their development and application in fields such as sensing and bioimaging. One potential advantage of employing CDs is using organic waste as carbon precursors in their synthesis, providing a pathway for waste upcycling for a circular economy. However, waste-based CDs often have low fluorescence quantum yields (QY), limiting their practical applications. So, there is a need for a well-defined strategy to consistently produce waste-based CDs with appreciable QY, irrespective of the starting waste material. Herein, we developed a fabrication strategy based on the hydrothermal treatment of waste materials, using citric acid as a co-carbon precursor and ethylenediamine as N-dopant. This strategy was tested with various materials, including corn stover, spent coffee grounds, cork powder, and sawdust. The results showed consistently appreciable QY, reaching up to ~40 %. A Life Cycle Assessment (LCA) study demonstrated that producing these waste-based CDs has lower environmental impacts compared to CDs made solely from commercial reagents. Thus, we have established a framework for the environmentally friendly production of CDs by upcycling different waste materials without significant sacrifices in performance (QY).
碳点（CDs）是具有卓越性能的荧光碳基纳米材料，这使得它们比传统荧光团更具吸引力。因此，研究人员专注于它们在传感和生物成像等领域的开发与应用。使用碳点的一个潜在优势是在其合成过程中使用有机废物作为碳前驱体，为循环经济中的废物升级回收提供了一条途径。然而，基于废物的碳点通常具有较低的荧光量子产率（QY），限制了它们的实际应用。所以，需要一种明确的策略来持续生产具有可观量子产率的基于废物的碳点，而不管起始废物材料是什么。在此，我们开发了一种基于对废物进行水热处理的制备策略，使用柠檬酸作为共碳前驱体，乙二胺作为氮掺杂剂。该策略用各种材料进行了测试，包括玉米秸秆、咖啡渣、软木粉和锯末。结果显示量子产率始终可观，高达约40%。一项生命周期评估（LCA）研究表明，与仅由商业试剂制成的碳点相比，生产这些基于废物的碳点对环境的影响更小。因此，我们建立了一个通过升级回收不同废物材料来实现碳点环境友好型生产的框架，且性能（量子产率）不会有显著牺牲。
