Controllable Synthesis of Hollow Pumpkin-like CuO/Cu2O Composites for Ultrasensitive Non-enzymatic Glucose and Hydrogen Peroxide Biosensors

Pumpkin-like CuO/Cu2O composites with different ratios were successfully fabricated by adjusting the hydrothermal reaction time and then their bifunctional catalyst capability was explored in glucose oxidation and H2O2 reduction. By comparing the peak potentials and peak currents, the CuO/Cu2O composites obtained at 24 and 30 h displayed the relatively highest performance for glucose and H2O2, respectively, and the corresponding mechanisms were also explained. Benefiting from the large active surface area and the synergistic effect of the optimal binary composition interfaces, the constructed sensors showed superior performance, with a sensitivity of 880 μA mM−1 cm−2, detection limit of 0.108 μM, and linear range of up to 15 mM for glucose together with a sensitivity of 5154 μA mM−1 cm−2, detection limit of 0.018 μM, and linear range from 0.005 to 1.05 mM for H2O2, as well as good selectivity, reproducibility, and stability, which were sufficient to meet the concentration requirements, enabling realizing the quantitative detection glucose in blood serum and H2O2 released from cells. This work provides a strategy to enhance the electrocatalytic activity of sensors and a promising platform for practical application.