Preparation of Ag-AgBr/TiO2-graphene and its visible light photocatalytic activity enhancement for the degradation of polyacrylamide

In current work, TiO2 was modified by Ag/AgBr semiconductor and graphene to enhance its photocatalytic activity for the degradation of polyacrylamide (PAM). Ag-AgBr/TiO2-graphene (AATG) composite photocatalysts were prepared by the deposition-precipitation method combining a subsequent calcination process. The structure, surface morphology and chemical composition of AATG composite photocatalysts were investigated by XRD, XPS, DRS, PL, SEM, EDS, TEM, and HRTEM methods. XRD and XPS results show that Ag-0 is generated from Ag+ under visible light irradiation. Degradation of PAM was chosen to evaluate photocatalytic activity using AATG composite as photocatalysts. The conditions such as mass ratio of TiO2/graphene, catalyst dose, pH and contact time, were investigated for the degradation of PAM. Possible pathway and mechanism were proposed for photocatalytic degradation of PAM over AATG composite photocatalyst under visible light irradiation. The prepared AATG composite photocatalyst can be separated from system effectively and easily; and exhibits significant photocatalytic activity after five successive recycles, which confirmed that the components of the AATG are not photo decomposed and the structure is stable during the photocatalytic process. (C) 2015 Elsevier B. V. All rights reserved.