Au纳米粒子负载的ZnO空心球复合材料的光生电荷转移行为及光催化活性

通过简单的两步法合成了不同负载量的Au/ZnO空心球。采用扫描电子显微镜(SEM)，X射线衍射(XRD)，X射线光电子能谱(XPS)及紫外-可见漫反射光谱(UV-Vis DRS)对样品的形貌、结构、组成和晶相等进行一系列的表征。以罗丹明B (RhB)为目标降解物，探究了Au/ZnO空心球的光催化活性。结果表明，适量Au修饰的ZnO光催化剂在混合光下20 min内对RhB的降解率达到73%。利用表面光电压谱(SPS)和瞬态光电压(TPV)技术，探讨了Au修饰后对ZnO光诱导电荷转移行为与光催化性能之间的关系。结果表明，混合光照下Au/ZnO空心球光降解性能的提高主要归因于作为电子受体的Au纳米粒子与ZnO之间形成的强的电子相互作用。适量Au纳米粒子的负载能够提高ZnO空心球中光生载流子的分离效率，相应地延长载流子的传输时间，增加光生电荷的寿命，从而促进其光催化活性的提高。

Photogenerated Charge-Transfer Properties of Au-Loaded ZnO Hollow Sphere Composite Materials with Enhanced Photocatalytic Activity

Au/ZnO hollow spheres with different mass ratios were synthesized by a simple two-step method. Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) were used to characterize the as-prepared Au/ZnO hollow spheres. The photocatalytic activity of the Au/ZnO composites was evaluated by the degradation of rhodamine B (RhB) dye under white light. Compared with pure ZnO hollow spheres, the degradation rate of RhB was enhanced by 73%with the appropriate amount of Au in the modified ZnO photocatalysts. The influence of Au decoration on the surface photo-induced charge-transfer behaviour of ZnO was investigated by surface photovoltage spectroscopy (SPS) and transient photovoltage (TPV). The results showed that the improved photodegradation by Au/ZnO hollow spheres was mostly caused by the strong electronic interactions between ZnO and the Au nanoparticles. The appropriate load of Au nanoparticles in ZnO promoted the separation of photogenerated charges, thus extending the transmission time of the charge carrier and increasing the lifetime of the photogenerated charges, resulting in highly efficient photocatalysis.