ZnO/Ag微/纳米晶的光化学合成及其光催化性质

Photochemical Synthesis and Photocatalytic Properties of Zno/Ag Nanocrystals

摘要: 采用简单的溶剂热法，以N,N-二甲基甲酰胺(DMF)和水作为溶剂，NH4BF4作为氟源，制备了蛋挞状的ZnO微/纳米结构。本文采用光化学还原法，在紫外光辐照下促使硝酸银在水/乙二醇混合溶剂中还原得到Ag纳米粒子，使之负载到所得ZnO表面进而得到ZnO/Ag复合材料，同时通过XRD (X-射线粉末衍射仪)，DRS (UV-Vis漫反射光谱)，SEM (扫描电子显微镜)，TEM (透射电子显微镜)表征了所得ZnO和ZnO/Ag的晶相和微观结构。SEM和TEM结果表明，得到直径为120 nm的Ag纳米片均匀地沉积在蛋挞状ZnO的表面。这种ZnO/Ag复合材料具有增强的可见光催化活性，由于与Ag纳米粒子杂化后ZnO的电子转移率增加，在可见光照射下，降解速率比蛋挞状ZnO快近5倍。

Abstract: Employing NH4BF4 as fluorine source, a simple solvothermal method was used to prepare ZnO microstructures with different morphologies by using N,N-dimethylformamide (DMF) and water as solvent. Moreover, by the reduction of silver nitrate in water/glycol mixed solvent on the surface of ZnO, ZnO/Ag composites were prepared via photochemical reduction method. The crystal phase and microstructure of the obtained ZnO and ZnO/Ag were characterized by XRD, SEM and TEM. The SEM and TEM results indicated that Ag nanodisks with diameters of 120 nm are uniformly deposited on the surface of hierarchical cake-like ZnO. Furthermore, the visible-light photocatalytic activity of the ZnO/Ag composites was evaluated by the degradation of Rhodamine B (RhB) under Xe lamp irradiation. Such unique ZnO/Ag composites showed an enhanced visible-light photocatalytic activity, the rate of degradation was nearly five times faster than that of bare hierarchical cake-like ZnO under visible-light irradiation due to the increase of electron-transfer rate of ZnO after hybridized with Ag nanoparticles.