Synthesis of V5+-doped Ag/AgCl photocatalysts with enhanced visible light photocatalytic activity

V5+-doped Ag/AgCl photocatalysts were prepared via the ion exchange method. The catalysts were characterized using X-ray diffractometry, transmission electron microscopy, and energy-dispersive X-ray, X-ray photoelectron, Fourier transform infrared and ultraviolet-visible spectroscopies. The V5+-doped Ag/AgCl photocatalysts show much higher photocatalytic activities than Ag/AgCl under visible light irradiation for methyl orange (MO) decomposition. Especially, the 2.0wt% V5+-doped Ag/AgCl photocatalyst shows the highest photocatalytic activity and also high stability after five cycles. The MO degradation rate during each cycle is almost maintained at 97%. Electron spin resonance spectroscopy and radical trapping experiments reveal that holes play an important role in the photocatalytic process.