Nonenzymatic hydrogen peroxide biosensor based on four different morphologies of cuprous oxide nanocrystals

In this work, we synthesized four different morphologies of cuprous oxide (Cu2O) nanocrystals (cube, rhombic dodecahedra, octahedra, and extended hexapod) by a hydrothermal method. Then, the four different morphologies of Cu2O were immobilized separately on a glassy carbon electrode (GCE) to construct a non-enzymatic hydrogen peroxide (H2O2) biosensor. We systematically explored the electrocatalytic activities of the four different Cu2O nanocrystals towards H2O2, which are strongly dependent on the shape of the Cu2O nanocrystals. It is shown that the modified electrodes exhibited excellent electrocatalysis for H2O2 reduction by electrochemical experiments. Moreover, the {111}-bounded extended hexapod Cu2O, {111}-bounded octahedral Cu2O and the {110}-bounded rhombic dodecahedral Cu2O nanocrystals are significantly more active than the {100}-bounded cubic Cu2O nanocrystals, as the {111} and {110} face contain copper atoms on the surface with dangling bonds, and are expected to interact more strongly with negatively charged ions or molecules.