Synthesis of Au/Cu2O/graphene quantum dots nanocomposites and its application for glucose oxidation

In this study, the novel Au/Cu₂O/Graphene quantum dots nanocomposites have been synthesized via a fast, simple and environmentally friendly method for the first time. Specifically, Cu₂O nanocubes (Cu₂O NCBs) synthesized by a reduction reaction at room temperature were combined with Au nanoparticles (Au NPs) and Graphene quantum dots (GQDs) obtained from low-cost and naturally abundant material. The synthesized Au/Cu₂O/GQDs were characterized by UV-vis, FTIR, XRD, TEM, FESEM, and EDS. The results show that the Au/Cu₂O/GQDs have an average size of about 32-36 nm, in which the diameter of Au NPs is ~28-32 nm, Cu₂O particles have the form of nanocube with the size of ~29-33 nm and GQDs are small spherical with an average size of ~5 nm. In addition, the electrochemical properties of the Au/Cu₂O/GQDs electrodes were investigated using the cyclic voltammetry (CV) technique. The obtained results show that the Au/Cu₂O/GQDs have high electroactivity, which are very potential and promising to be used in glucose sensor with a very wide concentration of glucose detection range from 10^-10 M to 1 M with a the LOD of 70 nM (7×10^-8 M) and a high sensitivity of 32.5 μAμM^-1cm^-2. Therefore, Au/Cu₂O/GQDs will be potential candidate for non-enzymatic sensitive glucose sensors in the future.

Graphical abstract

Cu₂O nanocubes (Cu₂O NCBs) were successfully combined with Au nanoparticles (Au NPs) and Graphene quantum dots (GQDs) to generate Au/Cu₂O/GQDs nanocomposites. The properties and morphology of synthesized Au/Cu₂O/GQDs were also studied. Au/Cu₂O/GQDs showed promising electrochemical activity and performed its applicability for glucose detection with a wide concentration of glucose detection range from 10^-10 M to 1 M.