可见光高催化活性GO/Ag3PO4/Ni复合薄膜的制备和性能

Preparation and Properties of Graphene-Oxide/Ag3PO4/Ni Composite Films with High Photocatalytic Activity under Visible Light

以磷酸铵和氧化石墨烯悬浊液的混合液为电解液,采用电化学共沉积法制备了Ag3PO4基GO/Ag3PO4/Ni复合薄膜。运用扫描电子显微镜(SEM)、能量色散谱(EDS)、X射线衍射(XRD)、拉曼光谱(Raman)和紫外可见漫反射光谱(UV-Vis DRS)等对其形貌、物相和光谱特性进行分析。最佳工艺制备的GO/Ag3PO4/Ni复合薄膜呈现出GO包覆在直径为100 nm左右的Ag3PO4纳米球外的表面形貌。GO片与Ag3PO4纳米球之间存在强电荷相互作用。与单独的Ag3PO4纳米球相比,GO片的附着导致带隙缩小,可见光区的吸收率增强。可见光下考察了复合薄膜降解罗丹明B的光催化活性和稳定性,并利用荧光光谱和捕获剂法对薄膜的光催化机理进行了探索。结果表明,GO片的加入不仅显著提高了Ag3PO4的光催化活性,而且提高了Ag3PO4的结构稳定性。光催化降解罗丹明B 60 min时,GO/Ag3PO4/Ni复合薄膜的降解率是Ag3PO4/Ni薄膜的1.32倍。在保持薄膜光催化活性基本不变的前提下可循环使用7次。GO优异的电荷传导性能,以及Ag3PO4纳米球与GO片之间的正协同效应是提高复合薄膜光催化性能的主要原因。

Ag3PO4 based-GO/Ag3PO4/Ni composite thin films were prepared by electrochemical co-deposition using a mixture of ammonium phosphate and graphene oxide aqueous suspension as electrolyte.Scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray diffraction(XRD),Raman and ultraviolet-visible diffuse reflectance spectroscopy(UV-Vis DRS)were employed to analyze the morphology,crystallinity and optical characteristics of the composite films.The results showed that the GO/Ag3PO4/Ni composite films prepared by the optimum process exhibited GO-coated surface morphology outside Ag3PO4 nanospheres with a diameter of about 100 nm.The strong charge interactions existed between GO sheets and Ag3PO4 nanospheres.As compared to Ag3PO4 nanospheres alone,the attachments of GO sheets led to a band gap narrowing and a strong absorbance in visible region.The photocatalytic(PC)activity and stability of the GO/Ag3PO4/Ni thin films were investigated by following the degradation of rhodamine B(RhB)under visible light irradiation.The PC mechanism of the composite films was explored by fluorescence spectroscopy and trapping agent method.Notably,the incorporation of GO sheets not only significantly enhanced the PC activity but also improved the structural stability of Ag3PO4.The efficiency of PC degradation of RhB under visible light irradiation 60 min was 1.32 times greater than that observed when a Ag3PO4/Ni thin film was used.GO/Ag3PO4/Ni thin films could be reused seven times without any significant decrease in the catalytic activity of the film.The excellent charge conductivity of GO and the positive synergistic effect between Ag3PO4 nanospheres and GO sheets are proposed to contribute to the improved PC properties of the composite films.