Enzyme-free Cu2O@MnO2/GCE for Hydrogen Peroxide Sensing

A novel composite material of copper (I) oxide at manganese (IV) oxide (Cu2O@MnO2), was synthesized and applied for modification on the glassy carbon electrode (GCE) surface (Cu2O@MnO2/GCE) as a hydrogen peroxide (H2O2) sensor. The composite material was characterized regarding its structural and morphological properties, using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The Cu2O@MnO2/GCE showed an excellent electrocatalytic response to the oxidation of H2O2 which provided a 0.56 s(-1) charge transfer rate constant (K-s), 1.65x10(-5) cm(2) s(-1) diffusion coefficient value (D), 0.12 mm(2) electroactive surface area (A(e)) and 1.04x10(-8) mol cm(-2) surface concentration (gamma). At the optimal condition, the constructed sensor exhibited a wide linear range from 0.5 mu M to 20 mM with a low limit of detection (63 nM, (S/N=3) and a good sensitivity of 256.33 mu A mM(-1) cm(-2). It also presented high stability (Delta I-response +/- 15 %, n=100), repeatability (1.25 %RSD, n=10) and reproducibility (3.55 %RSD, n=10). The results indicated that the synthesized Cu2O@MnO2 was successfully used as a new platform for H2O2 sensing.