木质素基石墨烯量子点的制备及其复合光催化剂的降解性能

Preparation of Lignin-based Graphene Quantum Dots and the Degradation Performance of Their Composite Photocatalyst

以木质素为原料,采用磷酸辅助的一步水热法制备了木质素基石墨烯量子点(lignin-based graphene quantum dots,LGQDs),对其进行分析与表征,研究磷酸掺杂量对LGQDs性能的影响。将LGQDs与g-C_(3)N_(4)进行复合,构建了g-C_(3)N_(4)/LGQDs复合光催化剂,进一步评价了该复合光催化剂对亚甲基蓝(MB)的光催化降解性能。研究结果表明:LGQDs具有明亮的蓝色荧光和良好的水溶性,这主要与表面丰富的官能团和磷元素的掺杂有关;在不同的p H环境下,LGQDs具有不同的荧光强度,且不同磷酸掺杂量影响了LGQDs荧光强度的稳定性;g-C_(3)N_(4)/LGQDs复合光催化剂对MB具有良好的光催化降解能力,降解率可达96.5%,相较于纯g-C_(3)N_(4)增幅为154.6%.

In this study,phosphoric acid assisted hydrothermal treatment was proposed and used to fabricate lignin-basedgraphene quantum dots(LGQDs).The resultant LGQDs were characterized,and the effects of phosphoric acid doping on LGQDs properties were investigated.The LGQDs were used to construct a photocatalyst with g-C_(3)N_(4),i.e.,g-C_(3)N_(4)/LGQDs,and the photocatalytic degradation ability of g-C_(3)N_(4)/LGQDs was evaluated by degrading methylene blue(MB).The results showed that LGQDs had bright blue fluorescence and good water solubility,which was mainly attributed to the abundant functional groups on LGQDs and phosphoric acid doping;the LGQDs showed different fluorescence intensities at different pH environments,and the phosphoric acid doping affected the stability of resultant LGQDs;the g-C_(3)N_(4)/LGQDs photocata-lyst showed good degradation ability for MB,i.e.,the photocatalytic degradation ability reached up to 96.5%,increased by 154.6%compared with that of pure g-C_(3)N_(4).