ZnO Nanosheets-Decorated ERGO Layers: An Efficient Electrochemical Sensor for Non-Enzymatic Uric Acid Detection

Abstract

Electrochemically reduced graphene oxide/zinc oxide (ERGO/ZnO) nanocomposite was simultaneously co-electrodeposited based on a one-step electrodeposition approach at room temperature on an indium tin oxide (ITO) electrode from an aqueous solution without using specific reducing agents. The electrochemical fabricated ITO-ERGO/ZnO electrode was characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and electrochemical impedance spectroscopy (EIS) techniques. The biosensor properties of the ITO-ERGO/ZnO electrodes were investigated in terms of their response toward uric acid (UA) sensing via enzyme-free amperometry. The linear current response for UA on the ITO-ERGO/ZnO electrode in the concentration range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1- 400\,\,\mu \text{M}$ </tex-math></inline-formula> with a sensitivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$150.7 ~\mu \text{A}$ </tex-math></inline-formula> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−2</sup> mM <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> was obtained. The main advantage of the ITO-ERGO/ZnO electrode was a relatively low detection limit for estimating UA, high selectivity, good repeatability, and long-term stability. In addition, the fabrication procedure of the designed biosensor was straightforward, practicable, and inexpensive.