Study On AgX/Carbon Material Visible Photocatalyst

The AC/AgBr composite visible light photocatalyst was prepared with activated carbon(AC),sodium bromide(NaBr)and silver nitrate(AgNO3)as the main precursors via a simple chemical precipitation approach.The AC/AgBr composites and pure AgBr were characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),UV-vis diffuse reflection spectroscopy(UV-Vis DRS),photoluminescence spectroscopy(PL),electrochemical impedance spectroscopy(EIS).The results indicated that the modification of AC can hardly change the crystalline and crystal size of AgBr particles,while significantly improve their specific surface areas,visible-light absorption and separation efficiency of photogenerated electron-hole pairs.The photocatalytic activities of different ratios of AC/AgBr composites were investigated by monitoring the degradation of MO and phenol under visible light irradiation.The results showed that the AC/AgBr composites exhibited more excellent visible-light photocatalytic activity than pure AgBr,and the highest visible-light photocatalytic activity was obtained for the composite with the AC and AgBr mass ratio of 1:100.The results of the cycle experiments revealed that the AC/AgBr composites exhibited drastically enhanced visible-light photocatalytic stability.The photogenerated electrons,holes and,hydroxyl radicals are responsible to the photodegradation of organic pollutants,and the photogenerated holes are the main active species.On the basis of the results and the properties of AC and AgBr,the visible-light photocatalytic mechanism of the AC/AgBr composites was discussed.A small amount of sucrose was adsorbed on the surface of AgBr particles via a dipping method,and the carbon/AgBr composites were prepared by carbonizing sucrose on the AgBr surface using concentrated sulfuric acid as were carbonizing agent.The as-prepared carbon/AgBr composites were characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),UV-vis diffuse reflection spectroscopy(UV-Vis DRS),photoluminescence spectroscopy(PL).The photocatalytic activity of the prepared samples was evaluated by the degradation of methylene orange(MO)under the visible light irradiation.The results showed that the visible-light photocatalytic activity of carbon/AgBr composites was obviously higher than pure AgBr.