Preparation And Properties Of Go/BiOI Composite Visible-light Photocatalytic Materials

A large number of toxic, carcinogenic pollutant have been entered into water,because of the rapid development of modern industry technology, thus has led toseriously threat to human healthy. At present, the photocatalytic technology has beenwidely used in the field of the energy development and pollution control. Manyrefractory materials or difficultly removing materials, such as polycyclic aromatichydrocarbons, chloroform, polychlorinated biphenyls （PCBS） and organic phosphoruscompounds, etc can be degraded by the photocatalytic technology. Photocatalyticreaction condition is mild, photocatalytic reaction can be carried through at roomtemperature and the organic pollutants can be degraded efficiently. Hence, thephotocatalytic technology has become a hot research at home and abroad.In this study, graphene oxide （GO） with high specific surface area and highdispersion properties and visible light catalytic materials BiOI were composited by theultrasonic assisted hydrolysis method. The structure, morphology and properties of thecomposites prepared under different condition were characterized by X-ray diffraction（XRD）, scanning electron microscope （SEM）, infrared spectroscopy （FT-IR）,ultraviolet-visible diffuse （DRS）. The effect of GO/BiOI composites prepared underdifferent conditions on the photocatalytic degradation properties of methyl orange wasstudied. At the same time, the mechanism of photocatalytic degradation of methylorange was discussed preliminarily. The specific research contents are as follows:（1） BiOI and GO/BiOI composite materials with visible light catalytic propertieswere prepared respectively by the ultrasonic assisted hydrolysis method. It can be foundthat in addition to the main crystal phase BiOI in the composites, a small amount ofBi₉I₂exist also.（2） The effect of different reaction temperature, different reaction time anddifferent composite ratio on the structure and morphology of BiOI in the GO/BiOIcomposite materials. It can be seen that the composite of GO and BiOI does not affectthe crystals structure of BiOI. But the effect of the reation condition on the morphologyof the GO/BiOI composite materials is big. The GO/BiOI composite materials assumesthe ellipsoid shape under the composite ratio of1:200, the reaction2h at80oC. （3） The visible light absorption properties of GO/BiOI composite materials wasstudied. The ability of visible light absorption properties of GO/BiOI compositematerials is higher than that of pure BiOI, and the visible light absorption of GO/BiOIcomposite materials exists the obvious red shift.（4） The visible light photocatalytic degradation efficiency of GO/BiOI on methylorange is significantly higher than that of pure BiOI. The rate of photodegradation of20mg/L methyl orange solution is95.7%under the visible light irradiation after3h inthe suspending system of GO/BiOI composite materials, which was prepared at80oCfor2h, composite ratio of1:200.（5） The mechanism of degradation of the GO/BiOI composite photocatalyst onmethyl orange was discussed preliminarily. The high photocatalytic properties ofGO/BiOI composite materials are due to the strong coupling effect between BiOI andGO. Under the visible light illumination, BiOI can produce the photoinducedelectron-hole pair, photoinduced electron can transfer from BiOI to GO through theinterface of GO and BiOI （GO as electron acceptor）, electron-hole composite iseffectively inhibited, thus the efficiency of the visible light catalytic efficiency isimproved.