自掺杂SnO2微球的水热合成及其可见光催化性能

本研究采用水热法,以柠檬酸为螯合剂,通过控制n(Sn⁴⁺)/n(Sn²⁺)的数值,合成了由具有丰富氧空位的SnO₂纳米晶体组装成的微球。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅里叶红外光谱(FT-IR)、X射线光电子能谱(XPS)及UV-Vis漫反射光谱对SnO₂纳米微球进行表征分析,结果表明:在酸性水热条件和柠檬酸的螯合作用下,二氧化锡纳米晶体聚集形成微球;在Sn⁴⁺/Sn²⁺摩尔比例为3:7时,其微球尺寸最小,整体分散性较好;同时适量二价锡离子的掺杂使得该样品氧空位浓度达到最佳,氧空位的存在将使得样品光吸收范围拓展至可见光,因而该样品显示出较强的可见光催化效率,在8 min内完全降解甲基橙。

Hydrothermal Synthesis and Visible Light Photocatalytic Properties of Self-Doped SnO2 Microspheres

In this study,the microspheres assembled from SnO₂ nanocrystals with abundant oxygen vacancies were synthesized by hydrothermal method using citric acid as a chelating agent and controlling the molar ratio of Sn⁴⁺/Sn²⁺.The SnO₂ nano-microspheres were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Fourier infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS)and UV-Vis diffuse reflectance spectroscopy.The results show that under the acidic hydrothermal conditions and the chelating effect of citric acid,the tin dioxide nanocrystals aggregate to form microspheres;at a Sn^4+/Sn²⁺molar ratio of 3∶7,the size of the microspheres is the smallest and the overall dispersion is good.The presence of the oxygen vacancies will extend the light absorption range to visible light;thus,the sample shows a strong visible light catalytic efficiency and complete degradation of methyl orange within 8 min.