Department of Chemistry, Deenbandhu Chhotu Ram University of Science & Technology, Murthal, Sonepat, 131039, Haryana, India.
Department of Chemistry, J. C. Bose University of Science & Technology, YMCA, Faridabad, 121006, Haryana, India.
Environ Sci Pollut Res Int. 2024 Nov;31(54):63408-63425. doi: 10.1007/s11356-024-35433-w. Epub 2024 Nov 2.
In this research work, nitrogen-doped carbon dots (N-CDs) adorned zinc oxide nanoparticles (N-CDs/ZnO) were successfully synthesized by a simple and cost-effective solution dispersion method and later on used as photocatalyst for decontamination of aqueous methylene blue (MB) dye on irradiation of UV light (300 W, 320-400 nm) at room temperature. Both the N-CDs and ZnO were prepared through green technique utilizing non-toxic, inexpensive and eco-friendly precursors, namely Foeniculum vulgare and Psidium guajava leaf extract, respectively. All the synthesized samples exhibited crystalline nature with average diameter of particle 4.42 nm, 12.38 nm and 14.11 nm corresponding to N-CDs, ZnO and N-CDs/ZnO, respectively. Further, band gap energy value (E) of 3.43, 2.76 and 2.49 eV for N-CDs, ZnO and N-CDs/ZnO, respectively, were obtained by using Tauc's plot. The photocatalytic capability of the sample N-CDs/ZnO was compared with bare ZnO nanoparticles, utilizing identical experimental conditions. The results demonstrated that the composite exhibited notably higher photocatalytic degradation efficiency than bare ZnO nanoparticles up to 15.54%. Lower band gap value of N-CDs/ZnO was the major factor for exhibiting this behaviour, decreasing the recombination rate and thus enhancing the efficiency. Furthermore, N-CDs/ZnO exhibited 98.17% MB degradation under optimized conditions (0.03 g, 5 ppm, pH 10). The resultant N-CDs/ZnO exhibited good stability and decontamination efficiency up to five cycles with efficiency loss of only 7.89%. Along with, trapping experiments was conducted to analyze the role of active species involved for deep understanding of mechanism. The order of efficiency of active constituents was observed to be: O > h > OH. The study analyzed the non-toxic nature of treated water, revealing normal plant growth, suggesting its potential use in irrigation of parks and roadside areas. Overall, present research work obeys the green chemistry principles with the fabrication of highly efficient, eco-friendly, cost-effective photocatalyst N-CDs/ZnO by utilizing the green precursors for the whole research work.
在这项研究工作中，通过简单且经济高效的溶液分散法成功合成了氮掺杂碳点（N-CDs）修饰的氧化锌纳米粒子（N-CDs/ZnO），并将其用作光催化剂，在室温下用紫外光（300 W，320-400 nm）照射，用于降解水中的亚甲基蓝（MB）染料。N-CDs 和 ZnO 都是通过利用无毒、廉价且环保的前体，即茴香和番石榴叶，分别采用绿色技术制备的。所有合成的样品均表现出结晶性质，颗粒的平均直径分别为 4.42 nm、12.38 nm 和 14.11 nm，对应于 N-CDs、ZnO 和 N-CDs/ZnO。此外，通过 Tauc 图获得 N-CDs、ZnO 和 N-CDs/ZnO 的带隙能值（E）分别为 3.43、2.76 和 2.49 eV。利用相同的实验条件，将样品 N-CDs/ZnO 的光催化性能与纯 ZnO 纳米粒子进行了比较。结果表明，与纯 ZnO 纳米粒子相比，复合材料表现出明显更高的光催化降解效率，最高可达 15.54%。N-CDs/ZnO 的较低带隙值是表现出这种行为的主要因素，降低了复合速率，从而提高了效率。此外，在优化条件（0.03 g、5 ppm、pH 10）下，N-CDs/ZnO 对 MB 的降解率达到 98.17%。所得 N-CDs/ZnO 表现出良好的稳定性和降解效率，在五个循环中效率损失仅为 7.89%。此外，还进行了捕获实验来分析参与的活性物质的作用，以深入了解机制。观察到活性成分的效率顺序为：O > h > OH。该研究分析了处理水的非毒性，发现植物正常生长，这表明它有可能用于公园和路边地区的灌溉。总的来说，本研究工作遵循绿色化学原则，通过利用绿色前体制备高效、环保、经济高效的光催化剂 N-CDs/ZnO，整个研究工作都使用了绿色前体。
