Tailored Core–Shell Au/ZnO Hybrid Nanostars for Photochemical Water Splitting

Nanostructured hybrids that combine metals and semiconductors exhibit significant potential as photocatalysts for various reactions. Among these, core–shell plasmonic noble metal–semiconductor nanostructures, such as Au/ZnO nanostars (NSs), are highly effective catalysts for photocatalytic water splitting. This study presents a simple method for synthesizing Au/ZnO NSs and comprehensively characterizes them by using various spectroscopic and microscopic techniques. The synthesized Au/ZnO NSs exhibit very high efficiencies in hydrogen (H2) and oxygen (O2) evolution when used as a catalyst for photocatalytic water splitting. This heightened photocatalytic activity can be attributed to the efficient suppression of the scavenging activity of Au nanoparticles. Additionally, the anisotropic star-shaped morphology of the Au component in the catalyst contributes to an increased surface area that promotes an enhanced interaction between the catalyst's components. This interaction facilitates facile interfacial charge transfer at the interface, resulting in an improved performance. Moreover, the plasmonic response of the Au core surrounded by ZnO nanostructures enhances the catalyst's light utilization capability, contributing to its superior performance. This synthesis method represents a significant advancement and paves the way for future developments in the design of plasmon-semiconductor nanostructures for energy conversion applications.