CSIRO Materials Science and Engineering, Clayton, Victoria 3168, Australia.
ACS Appl Mater Interfaces. 2012 Jan;4(1):476-82. doi: 10.1021/am201695c. Epub 2012 Jan 13.
The ability to decrease the electron/hole recombination rate, and decrease the band gap of titania to allow photoactivity on irradiation with visible light is attracting more and more attention. Here, boron doping of the titania, the deposition of gold nanoparticles, along with a meso-macroporous structure were obtained using a facile agarose gel templating process combined with sol-gel chemistry. The Au/B/TiO(2) nanocomposites were characterized using SEM, TEM, XRD, N(2) gas sorption, diffuse UV-vis, photoluminescence, and SIMS. The photocatalytic activity was assessed by degradation of an organic probe molecule (methylene blue) under visible light (λ > 420 nm). The resulting materials achieved photocatalytic activities up to 50% greater than the commercial Degussa P25 under visible light. The enhancement in photocatalytic activity was primarily attributed to the decrease in band gap as a result of the boron doping and its influence on the anatase to rutile phase formation: The doped materials were highly crystalline and an optimum anatase to rutile ratio (3:1) was obtained with 0.25 wt % boron in the sample calcined at 650 °C. In addition, the presence of the gold nanoparticles decreased recombination between the photoexcited electrons and holes, which further improved the photocatalytic activity.
能够降低电子/空穴复合率，以及降低二氧化钛的能带隙，从而在可见光照射下具有光活性，这引起了越来越多的关注。在此，采用琼脂糖凝胶模板法与溶胶-凝胶化学相结合的方法，制备了硼掺杂二氧化钛、金纳米粒子的沉积以及中孔-大孔结构。采用 SEM、TEM、XRD、N2 气体吸附、漫反射紫外-可见分光光度法、光致发光和二次离子质谱对 Au/B/TiO2 纳米复合材料进行了表征。通过可见光（λ>420nm）下有机探针分子（亚甲基蓝）的降解来评估光催化活性。所得材料在可见光下的光催化活性比商业 Degussa P25 提高了 50%以上。光催化活性的提高主要归因于硼掺杂导致的带隙降低以及其对锐钛矿向金红石相形成的影响：掺杂材料具有较高的结晶度，在 650°C 煅烧的样品中，硼含量为 0.25wt%时，锐钛矿与金红石的比例达到最佳（3:1）。此外，金纳米粒子的存在减少了光激发电子和空穴之间的复合，从而进一步提高了光催化活性。
