A feasible approach to synthesize Cu2O microcrystals and their enhanced non-enzymatic sensor performance

We have introduced potassium bromide (KBr) as an additive to synthesize cuprous oxide (Cu2O) microcrystals with various well-defined shapes. Here, the bromide ions play a pivotal role in controlling the shape of the Cu2O microcrystals, from concave cubic into short hexapod shapes. As a typical representative, the obtained Cu2O microcrystals were further utilized in a non-enzymatic amperometric glucose sensor. And the sensor constructed by the extended hexapod Cu2O microcrystals show the best performance, exhibiting remarkable sensitivity (97 mA mM(-1) cm(-2)), significant selectivity and a wide linear response (up to 14.3 mM) towards glucose detection. Compared with the previous sensors that were constructed by the Cu-based materials, this detection range is much closer to the glucose range in human serum. The wide range can be ascribed to the clean surface (with no organic capping agent adsorbed on the surface) and more rich {111} facets exposed for the extended hexapod structure, which maximize the accessible electroactive surface for the efficient transfer of electrons, as well as the product molecules. This work provides a green and feasible approach to enhance the Cu2O sensor performance, which can be extended to other applications such as solar-energy conversion and catalysis.