[en] Full text: Hybrid nanostructures are synthesized by combining two or more distinct nanomaterials into a single system. Such heterostructures often manifest synergistic effects between the connected components leading to useful multifunctional properties. In this work, we report a Pt@Au-ZnO type three component hybrid nanomaterial with novel photocatalytic properties. The photocatalytic properties were measured by monitoring the degradation of an organic dye molecule under UV illumination (365 ± 10 nm). It has been reported previously that Au-ZnO particles have better photocatalytic properties compared to bare ZnO nanoparticles. We found that Pt@Au-ZnO hybrid particles inherit superior photocatalytic properties compared to Au- ZnO particles. Most importantly, in the presence of Pt@Au-ZnO catalyst, modulation of the UV light (on/off) during the photocatalytic reaction did not influence the direction of the dye molecule degradation reaction. However, in the presence of Au-ZnO nanoparticles, reversion of the degradation reaction was noted upon turning off the UV light. Pt@Au-ZnO nanomaterials will be highly desirable for photocatalytic systems that utilize natural solar radiation as the light source, where fluctuations in light intensity can be expected. Synthesis, characterization (TEM, STEM, EDX and XPS), measurements and analysis of photocatalytic properties of Pt@Au-ZnO and Au-ZnO hybrid nanoparticles with different Au nanoparticle sizes will be presented. (author)