磷酸银纳米结构的调控及其光催化性能研究

基于十二烷基硫酸钠(SDS)、环己烷、异戊醇和水溶液构建的反相微乳液体系, 以硝酸银、磷酸二氢钾为原料, 通过改变水与表面活性剂物质的量比值(W)调控制备出棒状、纺锤状及四面体状磷酸银(Ag₃PO₄)纳米材料。利用XRD、SEM、TEM和UV-Vis-DRS光谱对样品结构、形貌以及可见光响应特性进行了表征, 探讨了不同形貌Ag₃PO₄的形成机理, 并以次甲基蓝(MB)降解效果评价了样品光催化性能。实验结果表明: 制备的系列纳米Ag₃PO₄均为体心立方结构晶体, 其形貌受W值影响明显; Ag₃PO₄形貌的不同主要由于SDS量的变化改变了含有产物水核的直径与界面膜强度。此外, 制备的样品均表现出好的可见光催化降解MB性能, 其中, 具有完整四面体形貌的Ag₃PO₄光催化性能最佳, 这与其能够裸露出多的{111}晶面有关。

Controlled Synthesis and Photocatalytic Activity Evaluation of Nanostructured Ag3PO4

Silver phosphate (Ag₃PO₄) materials with different nanostructures including rod, cambiform and tetrahedron with round edges and corners were synthesized by adjusting the molar ratio (W) of water to surfactant in a reverse microemulsion, which consists of sodium dodecyl sulfate (SDS), isopentyl alcohol, cyclohexane, and aqueous solution, using silver nitrate and potassium dihydrogen phosphate as starting materials. The structure, morphology and visible-light-response of the obtained samples were characterized by XRD, SEM, HRTEM, and UV-Vis-DRS spectra. The formation mechanisms of nanostructured Ag₃PO₄ were discussed. Moreover, the photocatalytic activity was also evaluated by means of degradation of organic dye methylene blue (MB) in water. The results show that all the samples have body-centred cubic crystal structure, and the W value has an obvious effect on morphologly of nanostructured Ag₃PO₄. The varied morphologies can be attributed to the change of diameter and interfacial film strength of water nuclear influenced by SDS content. In addition, all the obtained samples exhibit excellent efficient photocatalytic activity for the photo-degradation of methylene blue (MB) under visible light irradiation, and the tetrahedral Ag₃PO₄ with exposed many {111} facets exhibits the best photocatalytic activity.