Interparticle double charge transfer mechanism of heterojunction α-Fe2O3/Cu2O mixed oxide catalysts and its visible light photocatalytic activity

alpha-Fe2O3/Cu2O mixed oxide photocatalysts were prepared by one step facile hydrothermal method. During the synthesis, the growth of phase pure and highly crystalline polyhedral Cu2O crystals occurred and simultaneously a heterojunction formed between alpha-Fe2O3 and Cu2O particles. The optical band gap of bare Cu2O was found to be 1.8 eV which was less than the reported values and incorporation of 5 wt% alpha-Fe2O3 further reduced the band gap of Cu2O to 1.75 eV, indicating an enhanced absorption of visible light by the binary photocatalysts. More importantly, the loading of ce.-Fe2O3 on Cu2O augmented the charge carriers separation and transfer at the interface, which was evident by the reduced photoluminescence intensity of alpha-Fe2O3/Cu2O photocatalysts. The influence of different loading amounts of iron oxide (1-10 wt%) on Cu2O was evaluated. Among them, 5 wt% ce.-Fe2O3 loaded Cu2O showed the enhanced photodegradation activity due to the formation of an effective p-n heterojunction and exhibited nearly 30% and 95% increase in the photodegradation rate of methyl orange (MO) compare to bare Cu2O and ccFe(2)O(3), respectively. The photo generated superoxide radicals were found to be the main reactive species responsible for the degradation of MO. The excellent photodegradation activity of alpha-Fe2O3/Cu2O photo catalyst is mainly attributed to the enhanced visible light absorption, efficient charge carriers separation and transfer. Based on the experimental results, a double charge transfer mechanism was proposed for the separation and transfer of photogenerated charge carriers in the photocatalysts. (C) 2017 Elsevier B.V. All rights reserved.