Zhu Ziqi, Li Xinghui, Luo Min, Chen Minzhi, Chen Weimin, Yang Pei, Zhou Xiaoyan
College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China; Fast-growing Tree & Agro-fibre Materials Engineering Center, Nanjing 210037, China.
College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China; Fast-growing Tree & Agro-fibre Materials Engineering Center, Nanjing 210037, China.
J Colloid Interface Sci. 2022 Jan;605:330-341. doi: 10.1016/j.jcis.2021.07.016. Epub 2021 Jul 6.
The photocatalytic degradation of organic pollutant by carbon-based materials is still a challenge. Herein, xylose-derived carbon dots (X-CDs) and chitosan-derived CDs (C-CDs) were synthesized by heteroatoms-doping strategy. Although there is almost no difference in fluorescence emission behaviors, the two types of CDs demonstrated different advantages in photocatalysis and peroxymonosulfate (PMS) activation. Comparative research revealed that the X-CDs with doping of heteroatom S was superior in the separation of electron-hole pairs, resulting in a higher catalytic performance, while the S, N co-doped C-CDs can only exhibit high photocatalytic reactivity when they were coupled with PMS. The underlying reason is that the N-related functional groups with strong electron-donating property weakened the electron-trapping capacity of S-related energy level, but surface state resulting from this doping structures were conducive to promoting photo-generated electron transfer from C-CDs to PMS and played the primary role in organic oxidation. Thanks to the doping effect, both the X-CDs and C-CDs/PMS system displayed high photocatalytic performance for methylene blue removal under sunlight irradiation, showing almost 100% degradation efficiency in a 30 min period. The present study provides a valuable insight for the synthesis of CDs-based catalysts but also establishes a very promising catalytic oxidation system.
碳基材料对有机污染物的光催化降解仍是一项挑战。在此，通过杂原子掺杂策略合成了木糖衍生的碳点（X-CDs）和壳聚糖衍生的碳点（C-CDs）。尽管两种碳点在荧光发射行为上几乎没有差异，但它们在光催化和过一硫酸盐（PMS）活化方面表现出不同的优势。对比研究表明，掺杂杂原子S的X-CDs在电子-空穴对的分离方面更具优势，从而具有更高的催化性能，而S、N共掺杂的C-CDs只有在与PMS耦合时才表现出高光催化活性。其根本原因是具有强供电子性质的N相关官能团削弱了S相关能级的电子捕获能力，但这种掺杂结构产生的表面状态有利于促进光生电子从C-CDs转移到PMS，并在有机氧化中起主要作用。得益于掺杂效应，X-CDs和C-CDs/PMS体系在阳光照射下对亚甲基蓝的去除均表现出高光催化性能，在30分钟内降解效率几乎达到100%。本研究不仅为基于碳点的催化剂的合成提供了有价值的见解，还建立了一个非常有前景的催化氧化体系。
