The Preparation And Photocatalytic Activity Of Graphene-base Composite Photocatalyst

Photocatalysis based on semiconductor photocatalysts has been regarded as one of the mostatrractive green method to pure the water from the pollution. Ag₃PO₄ as novel Ag-basedphotocatalysts was first reported by Ye, which showed an excellent photocatalytic performanceduring the visible light irritation for oxygen production and pollutants degradation. Nowadays, tofurther improve the photocatalysis performance of Ag₃PO₄, much exploration forcused oncompositing it with other semiconductor photocatalysts. However, the poor ability to gather thepollutants of the composite photocatalysts which is an important fact to enchanced the photocatalyticperformance of Ag₃PO₄ also restricts their application. Assembly of graphene into graphenehydrogel（GH） by hydrophobic effect, π-π conjugate effect and electrostatic interaction, becomes anattractive material. GH with tremendous 3D porous can benefit the permeation of the pollutants tothe residuary oxygen-containing functional group on the surface of GH; the unique 3D network ofGH also provides support for the catalyst and prenvents the its aggregation. With residuary oxygen-containing functional group of GH, it’s also named as reduced graphene hydrogel（r GH）.Herein, we demonstrate a facile process for fabricating Ag₃PO₄/r GH composite materials using impregnation method. The Ag₃PO₄/r GH composite analysed by XRD, Raman, FTIR, XPS methods shows higher absorption ability for the BPA removal than that of Ag₃PO₄/AC and Ag₃PO₄/Al₂O₃. It takes only 10 min for Ag₃PO₄/r GH to reach the adsorption equilibrium with the adsorption capacity of 15mg/g. Meanwhile, the removal efficiency of BPA keeps much higher（almost 100%） during simultaneous adsorption and photocatalysis process with the light irradiation than that of the dark absorption process. Otherwise, in this article, we also investigate the absorption process as well as the absorption-photocatalysis synergistic process, using Ag₃PO₄/r GH to remove BPA for continuous flow operation. The outstanding synergetic effects between the absorption effect of r GH and the photocatalysis effect of Ag₃PO₄ with essential explanation of the mechanism make this study not only fundamentally important but also potentially practical applicable.