Pulsed laser-induced dewetting to fabricate Au-Pd nanoparticles supported on ZnO films and its application for the photocatalytic degradation of indigo carmine

Abstract

Gold-palladium (Au-Pd) bimetallic alloy nanoparticles (NPs) were obtained by the interaction of a laser pulse with a stack of Au and Pd thin films, these films were previously and sequentially deposited on a zinc oxide (ZnO) thin films grown on a glass substrate. This method can produce, with a single laser pulse, spherical NPs of different compositions which remain attached to the surface of the ZnO film. X-ray diffraction analysis showed that the NPs are composed of a solid solution of the metals whose relative content was modified by varying the deposition time of the starting metal films. The higher amount of Pd in the NPs, the smaller particle size being the minimum around 50 nm. To demonstrate the usefulness of this method to produce Au-Pd NPs directly on surfaces, the decorated ZnO layers were tested as photocatalysts material for the decomposition of indigo carmine dye. The bimetallic NPs supported on ZnO showed to have a better photocatalytic performance to decompose the dye than their mono-metallic counterpart and bare ZnO thin film. The bimetallic NPs richer in Pd achieved a degradation of 99% of the dye while bare ZnO film reached just 32%.