Electrospun Au nanoparticle-containing ZnO nanofiber for non-enzyme H2O2 sensor

In recent years, metal oxides, especially ZnO, have received extensive attention for non-enzyme biosensors. Au-ZnO composite nanofibers were prepared by one-pot electrospinning a dimethylformamide solution of chloroauric acid and zinc acetate containing polyacrylonitrile and polyvinylpyrrolidone followed by calcination. The morphology, composition, and crystal structure of the prepared Au-ZnO nanofibers were investigated by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction methods. The Au nanoparticles with a face-centered cubic structure were uniformly distributed on the fine ZnO nanofibers. The ZnO fiber with the diameter of 100 +/- 20 nm consisted of hexagonal wurtzite structural ZnO particle. Compared to the individual ZnO sample, the presence of Au nanoparticles retains the fibrous structure and enhances the electrical conductivity of the fibers, proved by cyclic voltammetry and electrochemical impedance analysis. By fine-tuning the molar ratio of Au/Zn in the precursor solution, the morphology of Au-ZnO can be controlled. The Au-ZnO composite fiber was used as an enzyme-like catalyst for the sensitive detection of H2O2 based on synergetic catalytic effect of Au nanoparticles and ZnO. Au-ZnO electrode with the Au/Zn atomic ratio of 0.24 shows the highest activity for H2O2 reduction. There was a good linear relationship between catalytic current and H2O2 concentration in the range of 1 x 10(-6)-6 x 10(-3) M (R-2 = 0.9994). The detection limit is calculated to be 0.1 x 10(-6) M (S/N>3). This Au-ZnO composite fiber can be used as a non-enzyme sensing material for the high sensitive and selective determination of H2O2.