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, Ag_67.3Au_32.7 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 Ag_67.3Au_32.7 bimetallic nanostructures are the most excellent candidate for enzyme-free H₂O₂ sensing.