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染料污染和大气中CO排放已成为日益严重环境问题,研发染料污染物的降解技术及低温CO催化氧化有助于解决上述问题。利用高分辨透射电子显微镜(HRTEM)和X射线衍射(XRD)等技术,该文比较了二氧化钛(TiO_2)介孔微球修饰金(Au)纳米颗粒前后的形貌、结构与组成的变化及催化染料降解和低温CO氧化的性能。结果表明,应用沉积-沉淀法可将Au纳米颗粒均匀地修饰在TiO_2介孔微球表面,颗粒直径约为4.5 nm。XRD结果显示Au~(3+)被还原为单质Au,且还原过程没有破坏TiO_2载体的晶体结构;电感耦合等离子体质谱(ICP-MS)测试得出Au含量仅为3.12%。氮气吸附-脱附等温曲线测试出Au/TiO_2比表面积为103.6 m~2/g,相应的Barret-JoynerHalenda(BJH)孔径分布测试出平均孔径为9.3 nm。有机染料罗丹明B(Rh B)的光催化降解结果显示,Au/TiO_2复合催化剂催化下的降解速率为6.63×10-5s-1,而单一TiO_2催化下的降解速率为5.18×10~(-5)s~(-1)。亚甲基蓝(MB)光降解实验显示出相同的结果,进一步证明Au/TiO_2复合催化剂具有较高的活性。低温催化CO氧化测试结果表明,单一TiO_2不具有催化活性,Au/TiO_2催化作用时在室温下CO转化率达48%,升温至50℃时CO转化率可达到99%,显示出很高的催化活性和热稳定性,并且可重复利用。可见,纳米Au/TiO_2复合催化剂在处理有机染料污染和低温CO氧化方面具有潜在的应用价值。
Dye pollution and atmospheric CO emission have become increasingly serious environmental problems. Research and development of dye pollutant degradation technology and low temperature CO catalytic oxidation help to solve the above problems. The morphology, structure and composition of titanium dioxide (TiO 2) mesoporous microspheres modified Au nanoparticles were compared before and after HRTEM and X-ray diffraction (XRD) Dye degradation and low temperature CO oxidation performance. The results show that Au nanoparticles can be uniformly modified on the surface of TiO 2 mesoporous microspheres by the deposition-precipitation method. The diameter of the particles is about 4.5 nm. The results of XRD showed that the Au 3+ was reduced to the simple Au, and the crystal structure of the TiO 2 support was not damaged by reduction. The content of Au was only 3.12% by inductively coupled plasma mass spectrometry (ICP-MS). The specific surface area of Au / TiO_2 was 103.6 m ~ 2 / g after nitrogen adsorption-desorption isotherm. The corresponding pore size distribution of Barret-Joyner Halenda (BJH) measured an average pore diameter of 9.3 nm. The photocatalytic degradation of rhodamine B (Rh B) showed that the degradation rate of Au / TiO 2 composite catalyst was 6.63 × 10-5s-1, while the degradation rate of single dye was 5.18 × 10 ~ (- 5) s ~ (-1). The methylene blue (MB) photodegradation experiment showed the same result, which further proved that the Au / TiO 2 composite catalyst had high activity. The results of CO oxidation at low temperature show that single TiO 2 has no catalytic activity, the CO conversion reaches 48% at room temperature under the catalysis of Au / TiO 2 and the CO conversion reaches 99% at 50 ℃, which shows a high catalytic activity Activity and thermal stability, and can be reused. It can be seen that the nano-Au / TiO 2 composite catalyst has potential application value in the treatment of organic dye pollution and low-temperature CO oxidation.