Immobilized Cu–Cr layered double hydroxide films with visible-light responsive photocatalysis for organic pollutants

Oriented Cu–Cr layered double hydroxide (LDH) films have been fabricated by the electrophoretic deposition method (EPD) on copper substrates, which can be used as photocatalysts for the degradation of organic pollutants under visible-light irradiation. Powder X-ray diffraction (PXRD), scanning electron microscope (SEM), Fourier transform infrared (FT-IR) and Brunauer–Emmett–Teller (BET) reveal that the resulting CuCr-LDH film possesses high crystallinity, porous structure as well as large specific surface area. UV–vis diffuse reflection spectroscopy (DRS) confirms that the CuCr-LDH film shows a broad absorption in visible light region (>400 nm). The LDH film thickness can be controlled precisely by adjusting voltage or time of EPD. The film with thickness of 16.5 μm shows excellent photocatalytic activity for the degradation of 2,4,6-trichlorophenol (2,4,6-TCP), sulforhodamine B (SRB) and Congo red. The photocatalytic reaction kinetics of 2,4,6-TCP was appropriately described by the pseudo-first-order model. In addition, the LDH film exhibits excellent recycleability compared with the corresponding powder sample, which facilitates its repeatable and cyclic usage over a long period. Owing to the high efficiency, low-cost preparation, easy manipulation and recyclability, it is expected that this film can be potentially used as photocatalyst in the field of water treatment.

► Oriented Cu–Cr layered double hydroxide films were prepared by the EPD method.
► The films exhibit effective photocatalysis for organic pollutants under visible light.
► The film catalyst shows excellent photocatalytic stability and recyclability.