In the present work, we report the comparative study of photocatalytic degradation of Rhodamine B (RhB) dye in aqueous solution by using ZnO-graphene nanaocomposites obtained using two different natural reducing agents namely Grape and Eichhornia crassipes. Graphene oxide (GO) was synthesized by Hummer’s method followed by reduction of the graphene oxide using natural reducing agents Grape and Eichhornia crassipes. The two samples of graphene oxide (Gr-rGO and Ei-rGO) were treated with ZnO to form a rGO-ZnO nanocomposites. The dye degradation was observed by the decrease in the absorption and decolorization in the presence of visible light. The degradation efficiency was found to be dependent on the concentration of rGO-ZnO nanocomposites added to the dye solution. The Ei-rGO has a higher adsorbing capacity due to its large surface area. A degradation efficiency of 67% was achieved by ZnO alone, whereas with the rGO-ZnO nanocomposite, the photocatalytic degradation efficiency for removal of RhB dye was found to be enhanced. The degradation efficiency was 70.0% and 97.5% with Gr-rGO-ZnO and Ei-rGO-ZnO nanocomposites respectively. The enhanced photocatalytic activity of Ei-rGO-ZnO composites could be attributed to the strong interaction with the ZnO and the defect sites available in Ei-rGO.

Graphical abstract of the carried work.

中文翻译：

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利用葡萄果实提取物和凤眼莲叶提取物合成还原氧化石墨烯/ZnO纳米复合材料，并比较它们降解罗丹明B染料的光催化性能。


在目前的工作中，我们报告了使用两种不同的天然还原剂（即葡萄和凤眼莲）获得的 ZnO-石墨烯纳米复合材料在水溶液中光催化降解罗丹明 B (RhB) 染料的比较研究。通过 Hummer 法合成氧化石墨烯 (GO)，然后使用天然还原剂葡萄和凤眼莲还原氧化石墨烯。用 ZnO 处理氧化石墨烯的两个样品（Gr-rGO 和 Ei-rGO），形成 rGO-ZnO 纳米复合材料。通过在可见光存在下吸收和脱色的减少来观察染料的降解。研究发现降解效率取决于添加到染料溶液中的 rGO-ZnO 纳米复合材料的浓度。 Ei-rGO由于其较大的表面积而具有较高的吸附能力。单独使用 ZnO 可以实现 67% 的降解效率，而使用 rGO-ZnO 纳米复合材料，去除 RhB 染料的光催化降解效率得到提高。 Gr-rGO-ZnO 和 Ei-rGO-ZnO 纳米复合材料的降解效率分别为 70.0% 和 97.5%。 Ei-rGO-ZnO 复合材料增强的光催化活性可归因于与 ZnO 的强相互作用以及 Ei-rGO 中可用的缺陷位点。

所进行工作的图形摘要。