Hassan Shawky M, Tarek Mahmoud, Samra Salem, El-Dafrawy Shady M
Chemistry Department, Faculty of Science, Mansoura University, Mansoura, Egypt.
Sci Rep. 2024 Nov 16;14(1):28275. doi: 10.1038/s41598-024-78719-2.
X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to investigate the structural, surface and particles properties of a series of zinc oxides (ZnO) doped with polyvinyl alcohol (PVA) that were prepared using the sol-gel method. The results demonstrated that the crystallinity of the catalysts decreased as the PVA content increased beyond 5 PVA/ZnO. However, on raising the calcination temperature up to 500 °C, the average crystal size of the PVA/ZnO nanoparticles increased. Next Pyridine adsorption was used to measure the surface acidity of the catalysts, and the results showed that doping ZnO with PVA and raising the calcination temperature to 500 °C increased the catalyst's surface acidity. Furthermore, the data indicates that raising the ratio of the Brønsted to Lewis acid sites enhanced the catalytic activity for the synthesis of coumarin derivatives. We concluded that the structural and acidity characteristics of the catalysts under study had a significant impact on the catalytic activity. Furthermore, a study examining the biological activity of ZnO/PVA and pure ZnO revealed that 5PVA/ZnO performed the best in terms of improving the kidney functions of diabetic rats.
采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究了一系列通过溶胶-凝胶法制备的掺杂聚乙烯醇(PVA)的氧化锌(ZnO)的结构、表面和颗粒性质。结果表明,当PVA含量超过5 PVA/ZnO时,催化剂的结晶度降低。然而,将煅烧温度提高到500℃时,PVA/ZnO纳米颗粒的平均晶体尺寸增大。接着用吡啶吸附法测定催化剂的表面酸度,结果表明,用PVA掺杂ZnO并将煅烧温度提高到500℃会增加催化剂的表面酸度。此外,数据表明,提高布朗斯特酸位点与路易斯酸位点的比例可增强香豆素衍生物合成的催化活性。我们得出结论,所研究催化剂的结构和酸度特性对催化活性有显著影响。此外,一项关于ZnO/PVA和纯ZnO生物活性的研究表明,5PVA/ZnO在改善糖尿病大鼠肾功能方面表现最佳。