The characterization of Sr-doped nanocrystal grain microspheres and photodegradation of KN-R dye

Sr-doped nanostructured crystalline TiO2 microspheres were fabricated by sol–gel reaction using reversed suspension polymerization as a template, followed by soaking in strontium nitrate solution. The morphology, crystal structure and photoabsorption ability was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV–vis spectrophotometer. The observation of SEM showed us that both the bare and Sr-doped microspheres presented the same honeycomb porous morphology. The XRD spectra affirmed that the incorporation of Sr was in the form of strontium titanate (SrTiO3) as eutectic structure with anatase TiO2. The photocatalytic efficiency of Sr-doped TiO2 microspheres was assessed by monitoring the photodecomposition of KN-R dye. The results revealed that Sr-doped microspheres provide higher efficiency than the unmodified, which is consistent with the analysis results of UV–vis absorption spectra. Obvious phenomenon of red-shift on UV–vis spectrum was seen comparison with the bare microspheres. Both the phenomena of red-shift and the photocatalytic activity improvement were attributed to the synergistic action between SrTiO3 and anatase TiO2. The degradation kinetics studies illuminated that the reaction was a representative zeroth order reaction.