. Schematic diagram of the CuO and CME preparation process (a), and XRD patterns of CuO (b) and SEM images of CuO (c-d)

. CV curves of different CMEs in blank and samples (a), EIS curves of the different CuO/Nafion-CMEs in 0.5 mol/L KCl solution and 10 mmol/L K₃Fe(CN)₆/K₄Fe(CN)₆ (b, c) with inset showing the equivalent circuit diagram, and the relationship between the electron transfer resistance (R_ct) and the CuO modified amount (d)

. LSV curves of the different CuO/Nafion-CMEs in sample solution (a) and relationship between the peak current, the peak potential and the CuO modified amount (b)

. CV curves of the S electrode in detection solution at different scan rates (a) and relationship between the oxidation peak current and the scan rate (b)

. I-t curves of the S electrode in blank solution with continuous dropping glucose (a), the relationship between the response current and the glucose concentration (b), the results of anti-interference experiments (c), and the stability experiments (d)

Table 1. Comparison of detection performances of the S electrode and those non-enzymatic glucose sensors reported elsewhere

Table 2. Data of recovery experiments of the S electrode for glucose