One‐Step Synthesis of β‐Cyclodextrin Functionalized Graphene/Ag Nanocomposite and Its Application in Sensitive Determination of 4‐Nitrophenol

β‐Cyclodextrin functionalized graphene/Ag nanocomposite (β‐CD/GN/Ag) was prepared via a one‐step microwave treatment of a mixture of graphene oxide and AgNO₃. β‐CD/GN/Ag was employed as an enhanced element for the sensitive determination of 4‐nitrophenol. A wide linear response to 4‐nitrophenol in the concentration ranges of 1.0×10^?8–1.0×10^?7 mol/L, and 1.0×10^?7–1.5×10^?3 mol/L was achieved, with a low detection limit of 8.9×10^?10 mol/L (S/N=3). The mechanism and the heterogeneous electron transfer kinetics of the 4‐nitrophenol reduction were discussed according to the rotating disk electrode experiments. Furthermore, the sensing platform has been applied to the determination of 4‐nitrophenol in real samples.