Fig.1. Schematic of the formation of BH-Ag/Pt NPs at different stages of
galvanic replacement process
Daqian Ma et al., successfully fabricated a non-enzymatic glucose sensor by immobilization of bimetallic hollow Ag/Pt nanoparticles (BH-Ag/Pt NPs) using the galvanic replacement reaction onto the surface of the pretreated pure Au electrode. The morphology and composition of the BH-Ag/Pt NPs were investigated by high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD), which proved the formation of bimetallic hollow Ag/Pt nanoparticles. The electroactive surface area and interface property of the Au electrode modified by BH-Ag/Pt NPs were measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The associated calculated values were 0.210 cm2 and 11.30 Ω cm2, which were distinctly higher than those of the pure Au electrode. The electrocatalytic properties of the modified electrode toward glucose oxidation were evaluated by CV and differential pulse voltammetry (DPV). The results showed that the modified electrode had a high electrocatalytic activity toward glucose oxidation, a linear response to the glucose concentrations ranging from 1 to 12 mM covering the physiological level of 3–8 mM with a current sensitivity of 7 μAmM−1 and a low detection limit of 0.013 mM. Moreover, the modified electrode also showed ideal reproducibility, long-term stability, and high selectivity. It also showed good glucometer test values for real samples. Therefore, both of the facile preparation method and the excellent properties of the Au electrode modified by BH-Ag/Pt NPs could potentially be implemented to develop novel non-enzymatic glucose sensors.
Daqian Ma, Xiaona Tang, Meiqing Guo, Huiran Lu & Xinhua Xu – Ionics, Springer- 2014