Synthsis And Characterization Of Nano SrTiO₃-based Materials In Photocatalytic Application

The photocatalytic technology under visible light is an important field with greatpractical value. After reviewing the synthetic methods of many visible-light-inducedphotocatalysts and their photocatalytic mechanism, nano-Fe-doped SrTiO3photocatalysts were synthesized via sol-gel method and their performances in thephotodegradation of methylene blue （MB） under visible light irradiation were studiedsystematically. The results showed that the above SrTiO3powders possessed highphotocatalytic activity，and had potential applications in the degradation of organicpollutants. The main results discussed in this article were as follows：The nano-Fe-doped SrTiO3powders were synthesized via sol-gel process, withdoping ratios of0.1,0.2,0.3and0.4. In the sol-gel process the appropriate range ofwater bath temperature （60℃⁸0℃）, pH values （4.0⁶.0） and the appropriate volumeof C2H6O （35mL⁴0mL）, H₂O （25mL³5mL）, C5H8O2（1.66mL².66mL） wasexplored. And the synthesized materials were characterized by X--ray diffraction（XRD）, UV-Vis diffusion reflection spectrum （DRS-UV-Vis）, scanning electronmicroscopy （SEM）, X-ray energy dispersive spectroscopy （EDS）. The XRD resultsindicated that the SrTiO3nanoparticles had the cubic perovskite phase while the grainsize was about20nm, and their lattice constant became smaller while increasing thecontents of Fe. It could be drawn that the Eg of the SrTiO3with Fe-doped ratios of0,0.1,0.2and0.3were3.19eV,3.05eV,3.01eV and3.09eV respectively from theDRS-UV-Vis spectra. In addition, the SrTiO₃sample with Fe-doped ratio of0.1haddefect levels at2.62eV. SEM and EDS results showed that the powders disperseduniformly while the particle size was less than100nm, and the Fe was well doped anddispersed uniformly.An efficient photocatalytic reaction system was established. Experimental resultsshowed that the nano-Fe-doped SrTiO3powders responded to visible light well andhad high photocatalytic activity. After40h, the degradation rates of MB could gain99%,99%,94.7%and96%under visible light as to the SrTiO3powders with Fe-dopedratios of0.1,0.2,0.3and0.4. The influence of doping ratio, sintering temperature anddosage of the photocatalysts on photocatalytic results were also studied, the resultsshowed that the doping ratios of0.1⁰.2, sintering temperature of700℃, dosage of0.0313mol/L could achieve good photocatalytic effect.