Cr掺杂SrTiO_3光催化材料中Cr的稳定性

Stability of chromium in Cr-doped SrTiO_3 photocatalyst

采用固相法制备了不同掺杂量、不同煅烧温度和不同取代位置的Cr掺杂SrTiO3样品,研究了其在不同pH值的溶液中Cr的稳定性。结果表明:即使掺杂量为1%,溶液中还是会有Cr相关的离子存在;溶液中Cr相关离子的浓度,随着掺杂量的增加而增大,随着煅烧温度的升高而减少。Cr在取代Sr位掺杂的样品中比取代Ti位掺杂的样品更稳定。Cr在中性溶液中最稳定,在酸性溶液中是以Cr3+离子存在,在中性和碱性溶液中以Cr2O27-与CrO24-离子存在。

The Cr-oped SrTiOa samples were prepared by the solid-state-reaction method using the Cr2 03, TiO2 and SrCOa as starting materials. The effect of doping amount, doping site and calcination temperature on the stability of chromium in Cr-doped SrTiO3 were investigated. The stability of Chromium in Cr-doped SrTiO3 was analyzed by measuring the UV-vis spectra of the solution obtained from filtering the mixture of Cr-doped SrTiO3 and aqueous solution with differ- ent pH value. The observed results indicated that the more the amount of Cr20a added, the more the amount of Cr20a re- mained. The samples of Cr substituted for Sr in SrTiO3 were more stable than that for Ti in SrTiO3. The higher calcination temperature was helpful for the Cr doping reaction.