Promising copper oxide-histidine functionalized graphene quantum dots hybrid for electrochemical detection of hydroquinone.

Abstract Hybrid of graphene with metal oxide has become one research hotspot in material science, because the hybrid may pave one new way to improve their electronic, chemical and electrochemical properties. The study reports one strategy for synthesis of copper oxide-histidine functionalized graphene quantum dots (CuO-His-GQD). First, Cu2+ ions react with His-GQDs to form Cu-His-GQD complex via the coordination between Cu2+ and His-GQD. The complex is oxidized in air to produce CuO-His-GQD hybrid. The as-prepared hybrid offers one three-dimensional architecture with the rich of open-porous structures. As the intimate chemical and electrical contact between the CuO and the His-GQDs was achieved, the hybrid of CuO with His-GQD creates a significant amplification of detection signal. The modified glass carbon electrode based on the CuO-His-GQD was used for differential pulse voltammetric detection of hydroquinone. Figures of merit include a wide linear response range (0.001–40 μM) and a 0.31 nM limit of detection at S/N ratio of 3. The sensor has been successfully applied in determination of hydroquinone in natural water samples. In addition, the study also provides an approach for fabrication of metal oxide-based nanocomposites with excellent electrochemical performance for sensing, catalysis, supercapacitors and lithium ion batteries. Graphical abstract Image 1 Highlights • We report synthesis of CuO-histidine-functionalized graphene quantum dots. • The hybrid offers three-dimensional structure with high porosity. • The sensing material provides high electrocatalytic activity for hydroquinone. • The sensor exhibits ultrasensitive electrochemical response towards hydroquinone. • The study provides a new approach for fabrication of metal oxide-based composite. [ABSTRACT FROM AUTHOR]