Noncovalent functionalization of graphene by CdS nanohybrids for electrochemical applications

•A simple noncovalent approach to synthesize graphene–CdS (GR–CdS) nanocomposites•Direct electrochemistry of glucose oxidase based on synergistic effect of GR–CdS•A sensitive glucose biosensor was fabricated based on the GR–CdS hybrids.

Graphene–CdS (GR–CdS) nanocomposites were synthesized via a noncovalent functionalization process. To retain the intrinsic electronic and mechanical properties of graphene, the pristine graphene was firstly modified with 1-aminopyrene based on a strong π–π bond between the pyrenyl groups and the carbon rings of the graphene. Then the CdS nanocrystals were uniformly grown on the amino-graphene. The GR–CdS nanocomposites were characterized by UV–vis spectroscopy and scanning electron microscopy. A glucose biosensor was then fabricated based on the as-prepared GR–CdS nanocomposite by immobilizing glucose oxidase (GOD) in a chitosan thin film on a glassy carbon electrode. Direct electron transfer between GOD and the electrode was achieved and the biosensor showed good electrocatalytic activity with glucose ranging from 0.5 to 7.5 mM and a sensitivity of 45.4 μA mM− 1 cm− 2. This work provided a simple and nondestructive functionalization strategy to fabricate graphene-based hybrid nanomaterials and it is expected that this composite film may find more potential applications in biosensors and biocatalysis.