ZnO纳米柱状阵列表面AgX等离子基元修饰及其可见光光催化活性

采用浸渍法制备了表面AgX（X=I，Br）等离子基元修饰的ZnO纳米柱状阵列，研究了浸渍浓度和时间以及紫外光光照预处理对ZnO纳米柱状阵列可见光光催化活性的影响.采用场发射扫描电子显微镜、X射线衍射仪、紫外可见漫反射吸收光谱以及X射线光电子能谱仪等手段对ZnO纳米柱状阵列的形貌、相组成、禁带宽度及其表面特性进行了表征.结果显示，AgBr颗粒分布于ZnO纳米柱状阵列的顶端及顶端侧面，同时AgBr颗粒之间相互接触而形成网状结构.通过紫外光光照预处理，AgBr表面出现细小颗粒，形成Ag/AgBr/ZnO纳米复合结构.可见光光催化降解甲基橙结果表明，在相同工艺条件下所制AgBr/ZnO的可见光光催化活性明显优于AgI/ZnO，且与浸渍浓度及时间有关.由于ZnO纳米柱状阵列的比表面积大，AgBr的可见光响应特性以及Ag/AgBr纳米结构的表面等离子效应，经过紫外光光照预处理形成的Ag/AgBr/ZnO纳米复合结构表现出最好的可见光光催化活性.

Plasmonic AgX nanoparticles-modified ZnO nanorod arrays and their visible-light-driven photocatalytic activity

AgX (X=I, Br) nanoparticles-surface modified ZnO nanorod arrays (AgX/ZnO) were prepared using an impregnation method. The influence of impregnating solution concentration, immersion time, and UV light illumination pretreatment on the visible light-driven photocatalytic activity of AgX/ZnO was evaluated. The morphology, phase composition, band gap, and surface characteristics of the AgX/ZnO nanorod arrays were assessed by field-emission scanning electron microscopy, X-ray diffraction, diffuse reflectance UV-Vis absorption spectroscopy, and X-ray photoelectron spectroscopy. The AgBr nanoparticles were homogeneously distributed on the top and side surfaces of the ZnO nanorods, and connected to form a porous network structure. Following UV light illumination pretreatment, Ag nanoparticles were formed on the surface of the AgBr nanoparticles producing a Ag/AgBr/ZnO nanostructure. Methyl orange photodegradation study showed that the photocatalytic activity of AgBr/ZnO was higher than that of AgI/ZnO, synthesized under similar conditions, and was highly related to the impregnating solution concentration and immersion time. Owing to the high surface area of the ZnO nanorod arrays, the visible light sensitivity of AgBr, and surface plasmon resonance of Ag/AgBr, Ag/AgBr/ZnO exhibited the highest visible light-driven photocatalytic activity.