▎ 摘　　要

In this study, an efficient route for graphene oxide (GO) and reduced GO (RGO) synthesis was developed by using an ultrasonic probe and bath alternatively. RGO was prepared in acidic and neutral conditions. The products were characterized via FTIR, XRD, Raman spectroscopy, SEM and AFM. Well-exfoliated and smooth sheets without crumples are observed in GO. The RGO synthesized in acidic media had fewer layers and smaller crystallite size than that derived from neutral condition. Electrochemical investigations revealed higher effective surface area and better electrocatalytic activity for the RGO synthesized in acidic media (RGO1). The electrochemical sensing ability of the glassy carbon electrode modified with RGO1 (RGO1/GCE) towards dopamine (DA) was examined using cyclic and differential pulse voltammetry methods. The evaluation of the pH and scan rate effect on the DA electrochemical response confirmed a reversible electrocatalytic pH-dependent oxidation reaction, controlled by a mixed adsorption-diffusion process at the RGO1/GCE. Retained low disorders on the basal plane and high defect on the edge sites of the layers have provided high electrocatalytic activity for RGO1 that make it suitable for (bio) sensing applications. [GRAPHICS]