Synthesis and characterization of n-ZnO/p-MnO nanocomposites for the photocatalytic degradation of anthracene

Abstract n-ZnO/p-MnO nanocomposites with different percentages of manganese (0.5%, 1.1%, and 2.25%) with a semiconducting junction were prepared. Changes in Flat band potential ( E fb ) for ZnO due the different amounts of MnO was observed, meanwhile same donor density ( N d ) was held in all materials. From chronoamperometric experiments under on-off illuminated conditions a transient time constant (τ), related to the electron transport in the electrodes were calculated, where higher values are observed in materials with high amounts of MnO. Photodegradation studies of anthracene in an ethanol:water (1:1, pH 12) solution were performed, showing that anthraquinone is the main product with no photodegrading of ethanol. The results suggest that the junction n-ZnO/p-MnO and materials with high transient time constant (τ), enhance the photocatalytic degradation. The best photocatalytic performance for the photodegradation of anthracene was obtained with the nanocomposite n-ZnO /p-MnO (Mn=2.25%) .