Abstract

Nitrogen-sulfur quantum dot co-modified graphene nanosheets composites (NSG) were fabricated via a facile hydrothermal method as a high performance metal-free catalyst for methyl orange (MO) degradation. Physical-chemical properties of the obtained samples were characterized by XRD, FTIR, SEM, TEM, EDX, TGA, BET, and UV–Vis DRS technologies. Compared with RGO, NSG exhibited much better photocatalytic performance for MO degradation under visible light, especially, NSG(30) showed the best photocatalytic degradation rate of 100% within 180 min. XRD, TG, and UV–Vis DRS results demonstrated that the addition of N and S can enhance the stability of oxygen containing functional groups to supply more adsorption active centers for organic contaminant molecular, adjust the band gap to a certain extent and increase the number of photogenerated electrons, improve the visible light utilization rate of the material and thus improve the photocatalytic degradation performance of the NSG composites. The degradation activity of the catalyst remained above 90% after 3 recycles. Finally, a possible photodegradation mechanism of MO on the obtained NSG sample was proposed.

中文翻译：

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氮和硫量子点共修饰的石墨烯纳米片具有增强的甲基橙降解光催化活性

摘要

氮-硫量子点共改性石墨烯纳米片复合材料（NSG）是通过一种简便的水热法制备的，是一种用于甲基橙（MO）降解的高性能无金属催化剂。通过XRD，FTIR，SEM，TEM，EDX，TGA，BET和UV-Vis DRS技术对获得的样品的物理化学性质进行了表征。与RGO相比，NSG在可见光下对MO的降解具有更好的光催化性能，尤其是NSG（30）在180分钟内表现出100％的最佳光催化降解率。XRD，TG和UV-Vis DRS结果表明，添加N和S可以增强含氧官能团的稳定性，从而为有机污染物分子提供更多的吸附活性中心，在一定程度上调节带隙并增加其数目。光生电子 提高了材料的可见光利用率，从而提高了NSG复合材料的光催化降解性能。3次循环后，催化剂的降解活性保持在90％以上。最后，提出了MO在所得NSG样品上可能的光降解机理。