Enhancing photocatalytic destruction of lignin via cellulose derived carbon quantum dots/g-C 3 N 4 heterojunctions.

Lignocellulosic biomass exhibits a promising potential for production of carbon materials. Nitrogen and phosphorus co-doped carbon quantum dots (N,P-CQDs) were fabricated via (NH ₄ ) ₂ HPO ₄ assisted hydrothermal treatment of cellulose pulp fibers. The as-prepared N,P-CQDs were characterized by HRTEM, FTIR, fluorescence and UV-vis, and then incorporated into g-C ₃ N ₄ (CN) through sonication and liquid deposition, forming N,P-CQDs/sonication treated g-C ₃ N ₄ (C-SCN) composites, which were then explored as photocatalysts. The photocatalytic ability of C-SCN towards model lignin was further analyzed. The results showed that, the fluorescence intensity and photoluminescence performance of N,P-CQDs were much higher than that of CQDs; the heterojunction was successfully constructed between the composites of N,P-CQDs and SCN; the incorporation of N,P-CQDs enhanced the visible light absorption, but reduced the band gap of the composite heterojunction; the resultant photocatalysts exhibited a good photocatalytic ability of model lignin via catalyze the fracture of β-O-4' ether bond and CC bond, i.e., the photocatalytic degradation ratio reached up to 95.5 %; and the photocatalytic reaction generated some valuable organics such as phenyl formate, benzaldehyde, and benzoic acid. This study would promote the high value-added utilization of lignocellulosic resources especially in the transformation of lignin, conforming the concept of sustainable development.
Competing Interests: Declaration of competing interest The authors declare that there are no financial and personal conflict of interest with other organizations or people that would influence the work. This manuscript has not been considered for publication anywhere. All authors agree to submit it to International Journal of Biological Macromolecules.
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