Ag/RGO@DE复合微粒的制备及光催化还原对硝基苯酚

为了有效还原污染水中的硝基化合物,采用原位法制备了具有高效催化活性的纳米银/还原氧化石墨@硅藻土(Ag/RGO@DE)复合微粒。利用SEM,XRD,XPS和FTIR等测试方法对所制备复合微粒的形貌、微观结构和组成进行了表征,采用UV-vis DRS,PL和光电流等测试分析了复合微粒的光电性能,以对硝基苯酚还原作为模型反应,考察了不同银和RGO负载量对Ag/RGO@DE复合微粒光催化性能的影响。结果显示,RGO为片层结构,纳米银颗粒分散于RGO和硅藻土DE表面及片层间,为面心立方晶型;纳米银的引入显著提高了RGO基体对可见光的吸收及其光生电子-空穴对的分离效率;当银质量分数为2.5%,RGO质量分数为26.6%时,Ag/RGO@DE表现出最佳的光催化还原活性。因此,Ag/RGO@DE复合微粒具有良好的光催化稳定性,对4-NP的还原反应具有高效催化活性。

Preparation of Ag/RGO@DE nanocomposite particles and photocatalytic reduction of p-nitrophenol

In order to effectively reduce nitro compounds in contaminated water, Ag/RGO@DE nanocomposite particles with high catalytic activity are prepared with an in-situ synthesis method. The morphology, microstructure and composition of as-prepared Ag/RGO@DE nanocomposite particles are characterized by SEM, XRD, XPS and FTIR, and the photoelectric property of the Ag/RGO@DE nanocomposite particles is characterized by UV-vis DRS, PL and photocurrent. The influence of different Ag and RGO load on catalytic activities of Ag/RGO@DE nanocomposite particles are examined by using the reduction of 4-NP as a model reaction. The results show that the RGO has lamellar structure, while the silver nanoparticles are face-centered cubic crystallites dispersing on the surface or between the lamellar of the RGO and diatomite. The visible-light absorption and electron-hole separation efficiency of RGO are improved by the introduction of silver nanoparticles. When the mass fraction of Ag is 2.5% and the mass fraction of RGO is 26.6%, the Ag/RGO@DE nanocomposite demonstrates the best photocatalytic activity. Ag/RGO@DE nanocomposite particles have satisfying stability and high catalytic activity for the reduction of 4-NP.