Perovskite La0.8Ba0.2Fe0.9Mn0.1O3-delta and LaFe0.9Mn0.1O3-delta were synthesized and characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), vibrating sample magnetometer (VSM), UV-vis absorption spectra and X-ray photoelectron spectroscopy (XPS) techniques. The magnetic properties of the La0.8Ba0.2Fe0.9Mn0.1O3-delta and LaFe0.9Mn0.1O3-delta were measured, and they were also evaluated for their photocatalytic activity toward the degradation of methyl orange (MO) under the sunlight irradiation. The effect of various parameters such as pH and irradiation time on the efficiency of photocatalytic degradation MO was studied. The experimental results show that the magnetic property of the La0.8Ba0.2Fe0.9Mn0.1O3-delta and LaFe0.9Mn0.1O3-delta was caused by the double exchange between Mn3+ and Fe3+, Mn3+ and Mn4+ as well as the defective state in them, the Ba-doping LaFe0.9Mn0.1O3-delta, i.e., La0.8Ba0.2Fe0.9Mn0.1O3-delta, has higher magnetic property than that of LaFe0.9Mn0.1O3-delta because of its higher Mn4+ content which favors the double exchange interaction between Mn4+ and Mn3+, and it has much higher photocatalytic activities than those of the LaFe0.9Mn0.1O3-delta due to its higher oxygen vacancies, higher Mn4+ content and higher visible light absorption. This new bifunctional La0.8Ba0.2Fe0.9Mn0.1O3-delta is extremely effective for the MO degradation, and it was easily separated by applied magnetic field and can be reusable and maintain relatively high activity. (c) 2012 Elsevier B.V. All rights reserved.