Novel visible light driven CuO/SmFeO3 nanocomposite photocatalysts with enhanced photocatalytic activities for degradation of organic pollutants

Several CuO(x)/SmFeO3 (x = 5, 8,10 and 20) hybrid nanocomposite photocatalysts were synthesized and characterized by XRD, FT-IR, TEM, SEM, EDS, DRS, UV-Vis, PL, elemental mapping and transient photocurrent responses analyses. The TEM images demonstrated that the SmFeO3 and CuO(10 wt%)/SmFeO3 particles were spherical like with average grain sizes of about 50 and 30 nm, respectively. The photoluminescence spectra of the CuO(x)/SmFeO3 composites depicted two emission wavelengths at approximately 360 and 430 nm. The Eg values of pure CuO, pure SmFeO3, CuO(5 wt%)/SmFeO3, CuO(8 wt%)/SmFeO3, CuO(10 wt%)/SmFeO3 and CuO (20 wt%)/SmFeO3 composites were measured equal to 132, 2.01, 1.91, 1.85, 1.81 and 132 eV, respectively. The photocurrent of the CuO(10 wt%)/SmFeO3 electrode was nearly 2 times higher than that of the pure SmFeO3 and CuO which was originated from a more efficient separation of photoinduced electron-hole pair. The highest photocatalytic efficiency of 65% was achieved under the visible light irradiation for the degradation of 8 mg.L-1 RhB dye using 0.15 g CuO(10 wt%)/SmFeO3 catalyst at pH = 5. The photocatalytic activity was reached to 100% using 0.05 mL of H2O2 under the above-mentioned optimized conditions. Moreover, the optimum CuO(10 wt%)/ SmFeO3 catalyst illustrated 93 and 85% performances for the degradation of 20 mg.L-1 RhB dye and phenol in presence of 0.05 mL H2O2 confirming the occurrence of both Fenton-like oxidation and photocatalytic mechanisms. The trapping experiments proved that the hydroxide radicals had a key role in degradation of RhB over the CuO(10 wt%)/SmFeO3 nanocomposite photocatalyst. Finally, it could be suggested that the CuO(10 wt%)/ SmFeO3 hybrid photocatalyst can find potential applications in industrial water treatment processes due to it is a highly stable and active sample. (C) 2018 Elsevier B.V. All rights reserved.