Photocatalytic Degradation of Organic Pollutants Using Al/TiO2 Composites Under Visible Light

Titanium dioxide (TiO2 ) has been widely studied as a photocatalyst owing to its advantages of low cost, good stability, and nonpollution. However, they can only be excited by ultraviolet light, resulting in low utilization of solar energy and limited photocatalytic efficiency. In recent years, researchers have found that the nonprecious metal Al can effectively improve the photocatalytic performance of TiO2 . However, the current studies focus only on enhancing the ultraviolet photocatalysis performance of semiconductors with Al on the substrate. In this study, Al nanoparticles (NPs) and TiO2 were prepared into composite materials. The effects of ligand, Al particle size, and the molar ratio of Al and TiO2 on the photocatalytic degradation of methylene blue (MB) by Al NPs and TiO2 composites (Al NPs/TiO2 ) were investigated. The results showed that the Al NPs/TiO2 prepared with a particle size of 200 nm of Al, glutathione as the ligand bridge, and an Al:TiO2 ratio of 2:1 were the most effective for the degradation of MB. The degradation rate of 5 mg/L MB solution within 70 min under visible light was up to 99.5%, which was three times higher than that of P25 TiO2 . The photocatalytic performance was further enhanced under sunlight with a degradation rate of 99.7% within 50 min, which is four times higher than that of P25 TiO2 under the same light source. Therefore, Al NPs/TiO2 is a potential photocatalytic material for the treatment of organic pollutants in water.