Design and engineering of high-performance photocatalytic systems based on metal oxide-graphene-noble metal nanocomposites

The present mini-review deals with recent developments in designing and engineering high-performance photocatalytic systems based on functional nanomaterials including molecular graphene, noble metals, and metal oxide nanostructures. Major research is focused on designing photo-functional systems with enhanced optical properties, charge separation, high charge transfer, and photocatalytic efficiency. Regarding these challenging issues, several metal oxide-based photocatalysts have been functionalized in various ways to improve their electrical and optical properties and enhance photocatalytic activity. The functionalization of metal oxide photocatalyst (ZnO/TiO2) nanomaterials by coupling with noble metal and/or graphene nanostructures has attracted considerable interest in the development of high-performance photocatalytic systems in recent years. These multicomponent nanocomposite systems composed of metal oxides, graphene (or its derivatives) and noble metals are highly significant as alternatives to extensively studied bi-component systems (e.g., metal oxide-graphene and metal oxide-noble metal systems) for the design of high-performance photocatalytic systems. The combination of metal oxides with graphene and noble metals provides improved optoelectronic properties due to the excellent electronic and surface plasmon resonance properties of these nanomaterials. This article first briefly explains the fundamentals of the various components and their roles in building efficient photocatalysts. Furthermore, recent developments in designing metal oxide-graphene-noble metal-based high-performance photocatalyst systems and engineering their properties are discussed with an emphasis on the associated mechanisms and their applications in various photocatalytic processes.