Synthesis of AG@AgCl Core–Shell Structure Nanowires and Its Photocatalytic Oxidation of Arsenic (III) Under Visible Light

摘要

Ag@AgCl core–shell nanowires were synthesized by oxidation of Ag nanowires with moderate FeCl~(3), which exhibited excellent photocatalytic activity for As(III) oxidation under visible light. It was proved that the photocatalytic oxidation efficiency was significantly dependent on the mole ratio of Ag:AgCl. The oxidation rate of As(III) over Ag@AgCl core–shell nanowires first increased with the decrease of Ag_(0) percentage, up until the optimized synthesis mole ratio of Ag nanowires:FeCl~(3) was 2.32:2.20, with 0.023?mg?L_(?1)?min_(?1) As(III) oxidation rate; subsequently, the oxidation rate dropped with the further decrease of Ag_(0) percentage. Effects of the pH, ionic strength, and concentration of humic acid on Ag@AgCl photocatalytic ability were also studied. Trapping experiments using radical scavengers confirmed that h_(+) and ·O~(2) _(?) acted as the main active species during the visible-light-driven photocatalytic process for As(III) oxidation. The recycling experiments validated that Ag@AgCl core–shell nanowires were a kind of efficient and stable photocatalyst for As(III) oxidation under visible-light irradiation.