Fig. 1. (a) Schematic illustration of the synthetic route for LS–rGO/GCE. (b) 20 mL rGO aqueous solution (0.5 mg mL⁻¹) before and after one week. (c) 20 mL LS–rGO (0.5 mg mL⁻¹) aqueous solution before and after two months. SEM images of (d) rGO and (e) LS–rGO surface.