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

Ag@AgCl core-shell nanowires were synthesized by oxidation of Ag nanowires with moderate FeCl3, 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 Ag0 percentage, up until the optimized synthesis mole ratio of Ag nanowires:FeCl3 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 Ag0 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 ·O2- 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.