Au改性纳米TiO2材料对NPE-10光催化降解的活性

以钛酸四丁酯和氯金酸为原料，通过溶胶凝胶法制备了Au掺杂的纳米TiO2光催化剂粉体，并用 XRD， BET，XPS和固体紫外可见吸收光谱等技术对其晶相结构，比表面积，表面组成及紫外可见光响应范围进行了表征，对其光催化降解非离子表面活性剂壬基酚聚氧乙烯醚（NPE-10）的活性进行了考察. 结果表明，掺杂的Au在纳米TiO2粉体材料中可能以两种形态存在，即以Au3+离子形式替代Ti4+进入TiO2晶格和以Au原子态形式暴露于粉体表面.前者使TiO2在480～650 nm出现了更强的光吸收，并大大地增强了粉体表面对氧物种的吸附；后者中处于表面原子态的Au又会成为光生电子的受体，有效地避免了光生电子空穴对的复合. 通过对掺杂量及处理温度的优化，在nAu3+/nTi4+=0.005， 500 ℃煅烧的条件下可以制得具有较高的光催化活性的Au/TiO2粉体. 对NPE-10的光催化氧化试验显示，日光照射4小时后降解效率可以达到91.8%；而用未改性的纳米TiO2，在同样条件下，NPE-10的光催化降解效率仅能达到50.2%，商品Degussa P-25也只能达到66%.

Photocatalytic Activity of Au Modified Nano-TiO2 for NPE-10 Degradation

The Au modified nanosized titanium oxide (TiO2) powders were prepared by sol-gel route at ambient temperature using Ti(OC4H9)4 and HAuCl4 as raw materials. The as-prepared samples were analyzed by XRD, BET, XPS and UV-visible absorption spectra technique. Photodegration for non-ionic surfactant Nonylphenyl poly(oxyethylene)ethers (NPE-10) has been carried out in air-equilibrated Au/TiO2 suspensions. The results suggest that the conformation of Au in the TiO2 composite was largely dependent on concentration of HAuCl4 during the preparation and the Au/TiO2 heat-treated temperature. The doped Au may take place Ti4+ in the lattices of TiO2 as Au3+ or exist at surface of TiO2 particles as atoms. The former may contribute to light adsorption range from.480 to 650 nm and may produce more O vacancies; the later may become the acceptor of photoinduced e- leading to a decrease of e-/h+ recombination. The preparation parameters were optimized by means of NPE-10 degradation. The optimized catalyst was obtained at Au/Ti molar ratio of 0.005 and calcined at 500℃. The degradation rate of NPE-10 could be up to 91.8% after irradiated 4 h in sunlight compared to 66% for the rate of TiO2-P-25 and 50.2% for the rate of no-doping TiO2 .