Heterojunction Nanowires of AgxZn1-xO-ZnO Photocatalytic and Antibacterial Activities under Visible-Light and Dark Conditions

We demonstrate the metallic silver (Ag) mixed with Zn (AcAc)(2) precursors to synthesize the heterojunction of AgxZn1-xO-ZnO nanowires through an ultraviolet-light (UV) decomposition process. The AgxZn1-xO-ZnO nanowires exhibited highly photocatalytic and antibacterial activities under visible-light illumination and dark conditions. The AgxO (1 < x < 2) peaks were demonstrated by the synchrotron radiation X-ray powder diffraction (SRXRD) patterns and X-ray photoelectron spectroscopy (XPS) spectra. The AgxZn1-xO-ZnO heterojunction nanowires significantly show a red-shift effect in the UV-visible absorbance spectra, implying that the nanowires exhibit photocatalytic activity under visible-light illumination. The Ag atoms acts as acceptor, and the Fermi level of AgxZn1-xO is more positive than the conduction band of ZnO so that the photoexcited electron of ZnO transfers to the AgxZn1-xO, giving rise to a better charge separation and thereby enhancing the photocatalytic activities of the AgxZn1-xO-ZnO nanowires. The R-factor-inhibiting activity for Escherichia coli can be reached by 5.6 under a visible-light (400-775 nm) irradiation and dark condition. Moreover, the nanowires can be implanted on a flexible and transparent poly(dimethylsiloxane) (PDMS) film for antibacterial touch screen applications. To the best of our knowledge, this is the first finding the high performance of photocatalytic and antibacterial activities under visible-light illumination and dark conditions made from the AgxZn1-xO-ZnO nanowires.