Department of Environmental Engineering, Zhejiang University, Hangzhou 310027, PR China.
J Colloid Interface Sci. 2010 Mar 1;343(1):200-8. doi: 10.1016/j.jcis.2009.11.012. Epub 2009 Nov 10.
N-doped TiO(2) (N-TiO(2)) nanocrystals with anatase and rutile mixed phases were prepared by partial oxidation of TiN. The samples were further modified by Fe-ions through incipient wetness impregnation method. The as-prepared samples were characterized by XRD, TEM, XPS, Raman, EPR, UV-vis DRS, and PL in detail. The results indicated that Fe mainly existed as Fe(3+)/Fe(2+) ions on the catalyst surface. The addition of small amounts of Fe-ions to N-TiO(2) nanocrystals caused several times enhancement of the photocatalytic activity under visible, UV and UV-vis light irradiation in degradation of gaseous toluene. The optimized Fe-ions content in this investigation was 0.02 wt.%. EPR and PL clearly showed that Fe(3+)/Fe(2+) redox cycle facilitated electron/hole charge separation, and contributed to the enhanced photocatalytic performance. Moreover, the photochemical stability of N-TiO(2) nanocrystals under visible light was improved due to the stabilization of nitrogen atoms in TiO(2) lattice by surface Fe-ions modification. The N-doped TiO(2) nanocrystals without Fe-ions modification suffered from a gradual deactivation due mainly to the loss of lattice-nitrogen during the photocatalytic reaction. The way to modification of nonmetal-doped TiO(2) nanomaterials brought new concept in enhancing the photocatalytic performance from the viewpoint of practical application.
N 掺杂 TiO(2)（N-TiO(2)）纳米晶具有锐钛矿和金红石混合相，通过 TiN 的部分氧化制备。通过初始湿浸渍法进一步用 Fe 离子对样品进行改性。通过 XRD、TEM、XPS、Raman、EPR、UV-vis DRS 和 PL 详细表征了所制备的样品。结果表明，Fe 主要以催化剂表面上的 Fe(3+)/Fe(2+)离子形式存在。在可见光、紫外光和紫外可见光照射下，少量 Fe 离子的添加使 N-TiO(2)纳米晶的光催化活性在降解气态甲苯方面提高了数倍。在本研究中，优化的 Fe 离子含量为 0.02wt%。EPR 和 PL 清楚地表明，Fe(3+)/Fe(2+)氧化还原循环促进了电子/空穴电荷分离，有助于提高光催化性能。此外，由于表面 Fe 离子修饰稳定了 TiO(2)晶格中的氮原子，因此在可见光下 N-TiO(2)纳米晶的光化学稳定性得到提高。没有 Fe 离子改性的 N 掺杂 TiO(2)纳米晶由于在光催化反应过程中晶格氮的损失而逐渐失活。这种非金属掺杂 TiO(2)纳米材料的改性方法为从实际应用的角度提高光催化性能带来了新的概念。
