Enhancing photocatalytic destruction of lignin via cellulose derived carbon quantum dots/g-C3N4 heterojunctions

• Published in: International journal of biological macromolecules Vol. 260; p. 129587
• Main Authors: Liu, Wei, Jiang, Chuang, Feng, Jinlong, Zhang, Liguo, Hou, Qingxi, Ji, Xingxiang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2024
• Subjects: Carbon quantum dots; Cellulose; Lignin; Photocatalysis; Lignin; Carbon quantum dots; Photocatalysis; Cellulose
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.129587

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 (NH4)2HPO4 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-C3N4 (CN) through sonication and liquid deposition, forming N,P-CQDs/sonication treated g-C3N4 (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. •Nitrogen and phosphorus co-doped CQDs was prepared from cellulose pulp.•N,P-CQDs exhibited a much better optical properties than CQDs.•N,P-CQDs/g-C3N4 composites were fabricated and explored as photocatalysts.•N,P-CQDs enhanced photocatalytic capacity of CQDs/g-C3N4 towards lignin model.•Some valuable chemicals were generated during the photocatalytic reaction.