Lignin-derived graphene quantum dots from phosphous acid-assisted hydrothermal pretreatment and their application in photocatalysis

Value- added utilization of carbon-rich lignin has become an urgent and attractive research topic due to its abundance, low cost, and sustainability. How to convert lignin in an efficient and green strategy is the bottleneck limiting its valorization. Herein, a phosphorous acid (P) assisted hydrothermal process to produce lignin-derived graphene quantum dots (P-LGQDs) was developed. The as-prepared P-LGQDs was comprehensively characterized, and explored in photocatalysis. The P-LGQDs have a narrow particle size distribution, excellent electronic and optical properties, and a good pH-responsiveness. The P-LGQDs was further used to construct P-LGQDs/g-C3N4 heterojunction, showing excellent photocatalytic degradation ability towards methylene blue and model lignin (94.6 % and 93.1 %, respectively). This present study offers a universal strategy for the value-added utilization and valorization of lignin.

Automated summary

The study introduced a phosphorous acid-assisted hydrothermal process for the production of lignin-derived graphene quantum dots, which exhibit excellent photocatalytic degradation ability towards methylene blue and model lignin when used in a heterojunction structure. This research offers a universal strategy for the value-added utilization and valorization of lignin.