A comprehensive study on the enhanced photocatalytic activity of Cu2O/BiVO4/WO3 nanoparticles

A ternary Cu2O-BiVO4-WO3 nano-composite was prepared and its catalytic activity was evaluated in the photodegradation of sulfasalazine (SSZ). The structural and compositional characterization of the composite was evaluated by XRD, TEM, and FE-SEM techniques. Its optical properties were also investigated by UV-vis diffuse reflectance spectroscopy (DRS) and photoluminescence spectroscopy (PL). The composite showed a boosted activity with respect to the individual semiconductors due to better charge carriers' separation. The increased charge separation of the composite was confirmed by the PL results. The composite showed weaker PL peaks than the single systems, showing slower e(-)/h(+) recombination. Both PL intensity and photodegradation efficiency depended on the mole ratio of the combined semiconductors in the composite. The mole ratio of 2:1:1 for the Cu2O/BiVO4/WO3 composite showed the best photodegradation activity. The optimal conditions were obtained at catalyst dose: 0.3 g L-1, Cssz: 8 mg L-1, initial solution pH: 3.75 and visible light irradiation time: 40 min. The pseudo-first-order rate constants of 0.013 min(-1) and 0.039 min(-1) (correspond to t(1/2) values of 53.31 min and 17.77 min) were obtained from UV-vis and COD results, respectively. The mineralization extents of 24, 44, 59, 77 and 85.7% were respectively obtained at irradiation times of 10, 20, 25, 40 and 50 min based on COD results.