Photocatalytic activity of Bi0.8La0.2FeO3−xK0.5Na0.5NbO3 ceramic powders

(1−x)Bi0.8La0.2FeO3−xK0.5Na0.5NbO3) (x = 0.00; 0.05; 0.10, 1.00) or ‘BLFO-KNN’ was prepared by the combustion method, using KNO3, NaNO3, NH4NbO(C2O4)2(H2O)2, Bi(NO3)⋅5H2O, La(CH3COO)3 and 5Fe(NO3)3⋅9H2O as starting materials. The microstructural features of the synthesized nanoparticles were characterized by X-ray powder diffraction and Raman spectroscopy. Rietveld refinement showed coexistence of orthorhombic-monoclinic phases for the powders obtained with x = 0.05 and 0.10. The photocatalytic activity of the BLFO-KNN, at different pH values, was investigated via degradation of rhodamine 6G (Rh6G) dye in a photoreactor equipped with commercial lamps that simulated sunlight. The results showed that BLFO can absorb visible light, whereas KNN absorbs in the ultraviolet range. There is a strong effect of the pH on the photocatalytic activity, with the highest activity for the Bi0.8La0.2FeO3 system at pH = 2 (~90% degradation efficiency for x = 0.0).