Anchoring Semiconductor and Metal Nanoparticle on Graphene Oxide for Simultaneous Sensing and Degradation of Contaminants

Manipulation of photoinduced charge transfer processes on a graphene based catalyst mat has allowed us to tailor the properties for photocatalytic and sensing applications. We have deposited luminescent CdSe quantum dots and SERS active silver nanoparticles to introduce photocatalytic and sensing properties. The role of the GO sheet is to establish electronic communication between semiconductor and metal NPs and promote adsorption of molecules near the silver nanoparticle surface. The GO-assisted communication between semiconductor and metal NPs in particular has enabled us to enhance the detection limit for low level nitroaromatic compounds in water. For example, CdSe emission is quenched upon adsorption of nitrobenzene. Following excitation with visible light the reduction of nitro group to amine proceeds at the CdSe surface and restores the emission.  Thus the multifunctional hybrid assemblies designed in this study enable us to achieve greater detection sensitivity as well as capability to degrade the organic contaminants from water.