▎ 摘　　要

Cuprous oxide (Cu2O) nanomaterials provide a versatile platform for building nonenzymatic glucose sensors. In particular, Cu2O nanocubes with controllable sizes and distributions can be deposited electrochemically on a conductive graphene strip as a soft substrate under different conditions, including overpotential, temperature, copper-ion electrolyte concentration, and deposition time. Graphene provides a promising substrate for sensing because of its high conductivity, high specific surface area, and unique thermal and mechanical properties. A more negative overpotential is found to produce smaller nanocubes with a large number density, while the deposition temperature could affect the morphology of nanocubes. The size of the nanocubes increases with increasing copper-ion concentration and deposition time. Using an optimal condition of -1.0 V vs Ag/AgCl, 1 mM [Cu2+], and 100 s deposition time at room temperature, we obtain a near-homogeneous monolayer of Cu2O-shell Cu-core nanocubes, similar to 50 nm in size, on a graphene strip substrate. The Cu2O nanocubes/graphene system is used as a high-performance sensor with a wide detection range of 0.002-17.1 mM and a high sensitivity appropriate for saliva-range glucose sensing. It has also been used to test glucose in the real saliva sample with 95% accuracy. This nonenzymatic glucose sensor is considerably better in performance than other nonenzymatic sensors, including those based on bare graphene, and graphene sputter-coated with a Cu film, and conventional enzymatic sensors such as glucose oxidase immobilized on graphene (with and without Nafion). In addition to being an excellent catalyst, Cu2O nanocubes have a large specific surface area and a large amount of active sites. These nanomaterial properties, along with the use of a high-conductivity substrate like graphene, make the Cu2O nanocubes/graphene sensor among the best saliva-range glucose sensors reported to date.