Facile synthesis of Ag@Cu2O heterogeneous nanocrystals decorated N-doped reduced graphene oxide with enhanced electrocatalytic activity for ultrasensitive detection of H2O2.

A nanohybrid composed of Ag@Cu 2 O heterogeneous nanocrystals supported on N-doped reduced graphene oxide (Ag@Cu 2 O/N-RGO) has been synthesized by a simple wet-chemical method. The resultant composite consists of N-RGO sheets fully and homogeneously coated with a dense layer of Ag@Cu 2 O nanocrystals. Both Ag and N-RGO are in direct contact with Cu 2 O, and Ag nanoparticles with sizes of 2–5 nm are mainly deposited on the surface of Cu 2 O cubes (edge length of 500 nm). The electrochemical studies reveal that the ternary Ag@Cu 2 O/N-RGO composite exhibit significantly enhanced electrocatalytic activity for H 2 O 2 sensing compared with either the single component (N-RGO) or two component systems (Cu 2 O/N-RGO and Ag/N-RGO), which is mainly due to the synergetic catalysis of the ternary system. The nonenzymatic sensor based on Ag@Cu 2 O/N-RGO composite shows overwhelmingly superior comprehensive performance for the H 2 O 2 detection over the documented Ag-based sensors. More specifically, it displays a rapid response (10 s) to H 2 O 2 over a wide linear range of 54–700 nM with a high sensitivity of 1298.3 μA mM −1  cm −2 and a low detection limit of 10 nM. Moreover, the sensor also exhibits the preferable selectivity in the presence of biologically coactive compounds accompanied with long-term stability and good reproducibility. [ABSTRACT FROM AUTHOR]