Ag–Au bimetallic nanostructures: co-reduction synthesis and their component-dependent performance for enzyme-free H2O2 sensing

Abstract

In this work, Ag–Au bimetallic nanostructures with various component ratios were successfully synthesized through a simple kinetic controlled co-reduction route at room temperature. The structure and composition of the as-obtained products has been adjusted and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectrometer (EDX) elemental mapping, inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and UV-visible spectra. Meanwhile, Ag67.3Au32.7 bimetallic nanostructures were identified to show the best sensing performance in the enzyme-free detection of H2O2 with a short response time (<5 s) at an applied potential of −0.5 V, a linear range from 0.01 to 68 mM (R2 = 0.998) with a lower detection limit of 0.2 μM and higher sensitivity of 600 μA mM−1 cm−2. More importantly, the component-dependent electrochemical sensor data of different component nanostructures has been studied, and the synergistic effect between Ag and Au can lead to the best performance of H2O2 sensing. The interaction of diffusion and adsorption we raised reasonably has been used to explain the component-depended performance. Significantly, this work supplies an understanding of the bimetallic component effect for H2O2 sensing by the control of the components of the Ag–Au bimetal, and find out the Ag67.3Au32.7 bimetallic nanostructures are the most excellent candidate for enzyme-free H2O2 sensing.