Enhanced photocatalytic performance of Au-Ag alloy modified ZnO nanocomposite films

摘要

Au-Ag alloy modified ZnO nanocomposite films have been prepared by sol-gel and spin-coating method. A visible-light absorption ability in the region of 450-550 nm due to the surface plasmon resonance effect of Au-Ag alloy was attained in the nanocomposite films along with a quasilinear relationship between the wavelength of the plasmon bands and Ag/Au precursor's molar ratio. The photocatalytic activity of the nanocomposite films for Rhodamine B (RhB) degradation under UV-light irradiation is enhanced by alloy-modification, which is related to the process of photocatalytic reaction as confirmed by the TOC results. The enhancement degree of photocatalytic activity strongly depends on the Ag/Au molar ratio, among which the Ag_(0.1)Au_(0.2)/ZnO photocatalyst provided the highest photocatalytic activity that is more than 2 times higher than the pristine ZnO photocatalyst as fabricated and tested under the same conditions.