Promotion effect of free Ag+ ions on photocatalytic dechlorination processes

Free silver ions (Ag+) in the solution exhibit enhanced photocatalytic dechlorination processes of organic chloride, including 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP), over copper phenylacetylene (PhC2Cu) under visible light irradiation. The concentration of AgNO3 remarkably affects the dechlorination activity of PhC2Cu. With the optimal concentration of 2 mM AgNO3, PhC2Cu showed the best photocatalytic performance, and the dechlorination rate of PhC2Cu was 2.3-fold enhanced under visible light irradiation for 80 minutes. This deep mechanism study demonstrated that free Ag+ in the solution, but not the deposited Ag particles on the surface of PhC2Cu, plays the most imported role in promoting the photocatalytic dechlorination process by forming the insoluble salt of AgCl.