:
In this article, we explored the possibility of controlling the reactivity of ZnO nanostructures
by modifying its surface with gold nanoparticles (Au NPs). By varying the concentration of Au with
different wt% (x = 0.01, 0.05, 0.08, 1 and 2), we have synthesized a series of (ZnO/Aux) nanocomposites
(NCs). A thorough investigation of the photocatalytic performance of different wt% of Au NPs on
ZnO nanosurface has been carried out. It was observed that ZnO/Au0.08 nanocomposite showed the highest
photocatalytic activity among all concentrations of Au on the ZnO surface, which degrades the dye
concentration within 2 minutes of visible light exposure. It was further revealed that with an increase in
the size of plasmonic nanoparticles beyond 0.08%, the accessible surface area of the Au nanoparticle decreases.
The photon absorption capacity of Au nanoparticle decreases beyond 0.08% resulting in a decrease
in electron transfer rate from Au to ZnO and a decrease of photocatalytic activity.
Background:
Due to the industrialization process, most of the toxic materials go into the water bodies,
affecting the water and our ecological system. The conventional techniques to remove dyes are expensive
and inefficient. Recently, heterogeneous semiconductor materials like TiO2 and ZnO have been
regarded as potential candidates for the removal of dye from the water system.
Objective:
To investigate the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface
and the effect of the size of Au NPs for photocatalytic performance in the degradation process.
Methods:
A facile microwave method has been adopted for the synthesis of ZnO nanostructure followed
by a reduction of gold salt in the presence of ZnO nanostructure to form the composite.
Results:
ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity which degrades the dye
concentration within 2 minutes of visible light exposure. The schematic mechanism of electron transfer
rate was discussed.
Conclusion:
Raspberry shaped ZnO nanoparticles modified with different percentages of Au NPs
showed good photocatalytic behavior in the degradation of dye molecules. The synergetic effect of
unique morphology of ZnO and well anchored Au nanostructures plays a crucial role.
