Green “planting” nanostructured single crystal silver

Abstract

Design and fabrication of noble metal nanocrystals have attracted much attention due to their wide applications in catalysis, optical detection and biomedicine. However, it still remains a challenge to scale-up the production in a high-quality, low-cost and eco-friendly way. Here we show that single crystalline silver nanobelts grow abundantly on the surface of biomass-derived monolithic activated carbon (MAC), using [Ag(NH₃)₂]NO₃ aqueous solution only. By varying the [Ag(NH₃)₂]NO₃ concentration, silver nanoplates or nanoflowers can also be selectively obtained. The silver growth was illustrated using a galvanic-cell mechanism. The lowering of cell potential via using [Ag(NH₃)₂]⁺ precursor, together with the AgCl crystalline seed initiation, and the releasing of OH⁻ in the reaction process, create a stable environment for the self-compensatory growth of silver nanocrystals. Our work revealed the great versatility of a new type of template-directed galvanic-cell reaction for the controlled growth of noble metal nanocrystals.