Synthesis and Ag-content-depended electrochemical properties of Ag/ZnO heterostructured nanomaterials

Ag/ZnO core/shell heterostructured nanomaterials were for the first time synthesized by Ag nanoparticle-mediated method, using which a novel hydrogen peroxide biosensor could be constructed. TEM and XRD measurements revealed that the Ag/ZnO heterojunctions were successfully acquired. Moreover, their sizes and shapes depended on Ag nanoparticles concentrations (i.e., Ag/ZnO-1, Ag/ZnO-2, and Ag/ZnO-3 heterojunctions were prepared using one-, two-, and three-fold Ag nanoparticles, respectively). Electrochemical measurements indicated that electrochemical properties of the Ag/ZnO-x-based biosensors also associated with the Ag nanoparticle content and the Hb–Nafion–Ag/ZnO-2 biosensor had the best electrochemical property, strongest redox peak currents and smallest ΔEp of about 40 mV. Moreover, the Ag/ZnO-2-based biosensor displayed excellent electrocatalytic properties such as wide linear range (2–540 μM), high sensitivity (83 mA cm− 2 mol− 1), low detection limit (0.18 μM), and good stability and reproducibility.

Research highlights
► Ag/ZnO nanoheterostructures were synthesized by Ag nanoparticle-mediated method.
► A biosensor was explored by combining the advantages of Ag and ZnO nanoparticles.
► Electrochemical properties of the biosensors depended on Ag nanoparticle content.
► Comparative experiments revealed that Ag/ZnO-2 biosensor had the best properties.
► The biosensors may open up a new idea for designing electrochemical biosensors.