Sr-doped nanostructured crystalline TiO2 microspheres were fabricated by modifying the bare microspheres with the method of soaking in strontium nitrate solution and heat treatment.The morphology,crystal structure and photoabsorption ability were characterized by scanning electron microscopy（SEM）,X-ray diffraction（XRD） and UV-Vis spectrophotometer.The observation of SEM showed 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 reveal that Sr-doped microspheres provided a higher efficiency than the unmodified,which was consistent with the analysis results of UV-Vis absorption spectra.Obvious phenomenon of red-shift on UV-Vis spectrum was seen in 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 reaction mechanism, reactivities, and apparent activation energies of epoxy/dicyanamide curing system accelerated by C6H5NHCONR2 (R=CH3, n-C4H9, i-C3H7,) werestudied by DSC and GC techniques. The results showed that in reaction of C6H5,NHCONR2with either dicyanamide or epoxy resin there was a dimethylamine released reacting with epoxy resin, giving a tertiary amine, which accelerated the anionic homopolymerization of epoxy resin.
