Photocatalytic Perfomance of ZnO-Graphene Oxide Composites towards the Degradation of Vanillic Acid under Solar Radiation and Visible-LED

Nanomaterials

Luisa M. Pastrana-Martínez¹  Álvaro Pérez-Molina¹  Sergio Morales-Torres¹  Neda Mirikaram¹  Francisco J. Maldonado-Hódar¹  Amir Salemi² 

[1] Department of Inorganic Chemistry, Faculty of Sciences, University of Granada, Avda. Fuente Nueva s/n, ES-18071 Granada, Spain;Environmental Sciences Research Institute, Shahid Beheshti University, Tehran 19839-63113, Iran;

关键词: graphene oxide;    ZnO;    vanillic acid;    water treatment;    scavengers;   

DOI  :  10.3390/nano11061576

来源: DOAJ

【 摘 要 】

Graphene oxide (GO) is used to enhance the photocatalytic activity of ZnO nanoparticles for the degradation of vanillic acid (VA) under simulated solar light and visible-LED (λ > 430 nm). ZnO-GO composites are prepared by a mixing and sonication process with different GO loadings (i.e., from 1.8 to 6.5 wt.%). The materials are extensively characterized by thermogravimetric analysis (TGA), physisorption of N₂, X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM), point of zero charge (pH_PZC), and UV-Vis diffuse reflectance spectroscopy (DRUV). The presence of GO increases the photocatalytic activity of all the prepared composites in comparison with the pristine ZnO. The highest photocatalytic activity is found for the composite containing 5.5 wt.% of GO (i.e., ZnO-GO5.5), reaching a VA degradation of 99% and 35% under solar light and visible-LED, respectively. Higher TOC removal/VA degradation ratios are obtained from the experiments carried out under visible-LED, indicating a more effective process for the mineralization of VA than those observed under simulated solar light. The influence of hole, radical, and non-radical scavengers is studied in order to assess the occurrence of the reactive oxygen species (ROS) involved in the photocatalytic mechanism. The study of the photo-stability during three reuse experiments indicates that the presence of GO in the composites reduces the photocorrosion in comparison with pristine ZnO.

【 授权许可】

Unknown