Conversion of Ag Nanowires to AgCl Nanowires Decorated with Au Nanoparticles and Their Photocatalytic Activity

A two-step approach has been developed to synthesize AgCl nanowires decorated with Au nanoparticles by using Ag nanowires as chemical templates. In the first step, the Ag nanowires are oxidized with FeCl3 followed by a simultaneous precipitation reaction between Ag+ and Cl- ions at room temperature, resulting in conversion of the Ag nanowires to AgCl nanowires as well as reduction of Fe3+ to Fe2+ ions. In the second step, the Fe2+ ions generated in the first step reduce Au precursors (e.g., NaAuCl4) to deposit Au nanoparticles on the surfaces of the AgCl nanowires, resulting in the formation of AgCl:Au composite nanowires. Because of strong surface plasmon resonance and chemical inertness of Au nanoparticles, the as-synthesized AgCl:Au nanowires exhibit enhanced absorption coefficient in the visible region and enhanced chemical stability to prevent them from degradation and aggregation. These unique properties enable the AgCl:Au nanowires to be used as a class of promising plasmonic photocatalysts driven by visible light. Preliminary results demonstrate these composite nanowires can efficiently decompose organics, such as methylene blue molecules, under illumination of white light.