1 research outputs found
Photocatalytic Perfomance of ZnO-Graphene Oxide Composites towards the Degradation of Vanillic Acid under Solar Radiation and Visible-LED
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 (pHPZC), 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.Spanish Project ref. RTI 2018-099224-B100 funded by
ERDF/Ministry of Science, Innovation and UniversitiesState Research Agency and the Nano4Fresh
project (ref. PCI2020-112045), as part of the PRIMA Programme supported by the European Unio