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

Abstract

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.