Mechanism and improvement of the visible light photocatalysis of organic pollutants over microcrystalline AgNbO3 prepared by a sol–gel method

Microcrystalline AgNbO3 photocatalysts were successfully prepared by a sol–gel method. The photocatalytic activities of the samples were evaluated by the degradation of various organic pollutants under visible light irradiation (λ ≥ 420 nm). The results indicated that AgNbO3 was favorable for adsorbing cationic dyes such as rhodamine B and methyl blue, and its photocatalytic performances were dominated by the adsorption abilities for different organic pollutants. For the degradation of rhodamine B, the sample prepared at 650 °C showed the highest photocatalytic activity and good stability due to its suitable surface area and crystallinity. On the basic of the experimental results, photo-induced holes were suggested as the main oxidation species for the pollutants decomposition over AgNbO3. Furthermore, the photocatalytic activity of AgNbO3 was greatly enhanced by the addition of an electron acceptor AgNO3. The enhanced photocatalytic mechanism was also discussed.