▎ 摘　　要

The graphene-Au nanocomposites were synthesized through hydrothermal route. Transmission electron microscopy (TEM) images gave direct evidence of the thin and transparent sheet structure of graphene. X-ray photoelectron spectroscopic (XPS) and X-ray diffraction (XRD) results also showed the presence of Au and the reduction of graphene oxide. As a model, myoglobin (Mb) was entrapped onto the nanocomposite modified glassy carbon electrode (GCE) and applied to construct a sensor. The immobilized Mb showed a pair of well-defined redox peaks and high catalytic activity for the reduction of H2O2. The biosensor with a linear range from 0.1 to 1.5 mu mol.L-1 and a detection limit of 0.05 mu mol.L-1 (S/ N = 3) showed good selectivity, reproducibility and stability. The graphene-Au nanocomposites provide a novel matrix for protein immobilization and the construction of biosensors via the direct electron transfer of protein.