Photocatalytic activity of Ag doped CuFe2O4 nanoparticles supported on reduced graphene oxide for the degradation of organic dyes under visible light irradiation

This study aimed to synthesize a new magnetic photocatalytic nanosystem composed of Ag-CuFe2O4@rGO and to investigate its photodegradation efficiency for two organic pollutants of methylene blue (MB) 4-nitrophenol (4-NP) under visible light irradiation. The synthesized Ag-CuFe(2)O(4)4@rGO nanocomposites were fully characterized by XRD, TEM, HRTEM, XPS, FTIR, UV and PL analysis which shows well controlled small sized (similar to 10 nm from Scherrer formula) CuFe2O4 NPs with dense and compact loading over rGO sheets. XRD results reveal that cubic spinel structure of CuFe2O4 with nanoparticles (5-10 nm) in shape, which is uniformly, decorated on the surface of the rGO sheets. The band gap energy values of CuFe2O4, Ag-CuFe2O4 and Ag-CuFe2O4@rGO nanoparticles are calculated as 2.76, 2.27 and 2.03 eV, respectively. After incorporation of Ag and rGO into CuFe2O4, the specific surface area was significantly improved to 154 m(2)/g for Ag-CuFe2O4@rGO nanocomposite. Upon inclusion of the photocatalysts, photodegradation efficiency increased and the Ag-CuFe2O4@rGO composite showed the highest efficiency towards MB (99.5%) and 4-NP (88.7%) followed by the Ag-CuFe2O4. With addition of rGO, the electron-hole recombination declines, thus resulting in a more optimum photocatalytic performance. The rate constant of Ag-CuFe2O4@rGO composite was found to be 0.0985 min-1 for MB and 0.0542 min(-1) for 4-NP, respectively. Moreover, the effect of pH, catalyst dosage, and long term stability was thoroughly determined. The improved performance could be attributed to the positive synergistic effect between CuFe2O4 nanoparticles and rGO. The samples were further evaluated by EIS and dynamic photoresponse in order to identify the charge transfer efficiency. The improved photocatalytic mechanism was also explained briefly.