Engineering the metathesis and oxidation-reduction reaction in solid state at room temperature for nanosynthesis.

It is a long-standing goal to explore convenient synthesis methodology for functional materials. Recently, several multiple-step approaches have been designed for photocatalysts Ag(n)X@Ag (X = Cl(-), PO4(3-), etc.), mainly containing the ion-exchange (metathesis) reaction followed by photoreduction in solution. But they were obsessed by complicated process, the uncontrollability of composition and larger sizes of Ag particles. Here we show a general solid-state route for the synthesis of Ag(n)X@Ag catalysts with hierarchical structures. Due to strong surface plasmon resonance of silver nanoparticles with broad shape and size, the Ag(n)X@Ag showed high photocatalytic activity in visible region. Especially, the composition of Ag(n)X@Ag composites could be accurately controlled by regulating the feed ratio of (NH2OH)2 ·H2SO4 to anions, by which the performance were easily optimized. Results demonstrate that the metathesis and oxidation-reduction reactions can be performed in solid state at room temperature for nanosynthesis, greatly reducing the time/energy consumption and pollution.