Facile synthesis of γ-Fe2O3/BiOI microflowers with enhanced visible light photocatalytic activity

Abstract

The composite materials of γ-Fe2O3/BiOI are synthesized by sol-gel and microwave hydrothermal method, in which γ-Fe2O3 is the magnetic carrier. The composition and property of the composite catalyst are studied by XRD, TEM, XPS, and UV-vis DRS methods etc. The results show that γ-Fe2O3 is uniformly distributed around BiOI nanosheets in the γ-Fe2O3/BiOI sample, thus making the p-n heterojunction composite catalyst material which features the band gap of 1.75 eV, the average pore size of 6.756 nm, the specific surface area of 46.722 m2/g and good superparamagnetism. It is also used to degrade organic dyes (methyl orange, MO) and antibiotics (sulfapyridine, SP) in waste water. Irradiated by tungsten lamp for 120 min with the composite catalyst material as the catalyst, MO has the photocatalytic degradation efficiency of 67.6% and SP of 64.1%, 20% and 30% higher than those when pure BiOI is used as the catalyst, respectively. The composite catalyst still maintains excellent catalyst efficiency after five times recycling. The enhanced catalytic performance of the composite material is attributed to the effective separation of the electrons and holes in p-n heterojunction built by γ-Fe2O3 and BiOI. The active species of the photodegradation process were h+ and •OH.