Pure and Gd3+, Tb3+ and Ho3+-doped As2Ni3O8: A new visible light induced photocatalyst for the photodegradation of malachite green water pollutant

Nanostructured doped As2Ni3O8 samples were synthesized via facile one step solid state reactions at 850 °C for 8 h using As2O3, Ni(NO3)2.6H2O, Gd2O3, Tb2O3 and Ho2O3 raw materials. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique. The rietveld analyses showed that the obtained materials were crystallized well in monoclinic crystal structure with the space group P121/c1. The morphology of the synthesized materials was studied by field emission scanning electron microscope (FESEM). Photocatalytic performance of the as-synthesized sample was investigated for the degradation of pollutant Malachite Green (MG) in aqueous solution under direct visible light irradiation. The light source was a white color fluorescent lamp with the 40 W power and light intensity of 1.34 W/m2 measured by a digital lux meter. The distance between the lamp and the surface of the solution was 50 cm. The degradation yield at the optimized condition (0.1 mL H2O2, 60 mg catalyst and 90 min) was 94 % for pure Ni3As2O8.