Synthesis of sp-hybridized nitrogen doped ultrathin graphdiyne and application to the electrochemical detection for 6,7-dihydroxycoumarin

As a new type of carbon nanomaterial, graphdiyne (GDY) has unique sp hybridized carbon atom, which makes it possible to develop new nitrogen-doped configurations. In this paper, sp-hybridized nitrogen atom doped ultrathin graphdiyne (NUGDY) was prepared based on graphdiyne oxide and melamine by carbonization at high temperature. NUGDY not only preserves the typical folded and wrinkled two-dimensional morphology of GDY, but also presents a three-dimensional porous network structure, which provides sufficient interface and capacity for the loading of target analyte. Meanwhile, N doping increases the GDY defects with more active sites and higher conductivity. Then, NUGDY was modified on the surface of carbon ionic liquid electrode and the modified electrode was applied to 6,7-dihydroxycoumarin (6,7-DHC) analysis. Cyclic voltammetry, electrochemical impedance spectroscopy and chronocoulometry results show that NUGDY has good promotive effect to the electrode performances. Differential pulse voltammetric experiments show that this electrochemical sensor has a low detection limit as 2.3 nM (3S0/S) for 6,7-DHC with high sensitivity. In addition, the modified electrode has the characteristics of excellent anti-interference ability and stability, and been successfully used in the real samples determination, which provides a promising method for the sensitive detection of drug molecules.