photocatalytic degradation of water pollutant dye by solidstate synthesized ni_1-xln_xsb_2o_6 (ln=eu, gd, ho and yb)nanocomposites

Nanostructured ni_1-xln_xsb_2o_6 (ln = eu, gd, ho and yb) powders were synthesized viastoichiometric 1:2 ni:sb molar ratio by solid state reaction at 800 ºc for 8 h using ni(no3)2,sb_2o_3, eu_2o_3, gd2o3 and ho_2o_3 raw materials. the synthesized materials were characterized byx-ray diffraction (xrd) technique. structural analyses were done by fullprof program employingprofile matching with constant scale factor. the results showed that the patterns had a mainorthorhombic nisb_2o_6 crystal structure with p42/mbc space group. the morphologies of thesynthesized materials were studied by field emission scanning electron microscope (fesem)which showed that the synthesized samples had sponge morphology. ultraviolet – visible (uvvis)spectroscopy showed that the smallest direct optical band gap energies were in the rangesof 1.6 to 1.8 ev suggesting a high efficient photocatalytic activity. photocatalytic performance ofthe synthesized nanomaterials was investigated for the degradation of pollutant malachite green(mg) in aqueous solution under visible light condition. it was found that the optimum conditionswere 0.04 ml h_2o_2, 30 mg catalyst, and 35 min reaction time. it was found that the synthesizednisb_2o_6 nanocatalyst had very good efficiency in aqueous solution under the optimized conditionsat the presence of visible light irradiation. the degradation yield at the optimized conditions was96 %. the optimum photocatalytic condition was used to study the performance of the othersynthesized materials in the photocatalytic degradation process.