【作者】 任沁锋；

【导师】 李家麟；

【作者基本信息】 华中师范大学 ， 材料物理与化学， 2007， 硕士

【摘要】 由于纳米材料有特殊的结构和优异的性质，使之成为材料科学领域研究的热点。特别是在光催化领域，可利用纳米半导体光催化剂降解废水。目前常用的纳米半导体催化剂是TiO₂和ZnO。两者都有较好的光催化效果，但他们需要紫外线激发。另外，Fenton试剂由于能产生具有强氧化性的·OH，在处理污水中被广泛的研究，但通常Fenton反应要消耗大量的双氧水或电能而使其应用受到一定的限制。氧化亚铜（Cu₂O）是少有的能够被可见光激发的半导体材料。普通的Cu₂O的禁带宽度为2.1eV，可用于太阳光下的催化反应。早在1998年，Ikeda等人的研究表明微米级别的Cu₂O在阳光照射下具有较好的催化性能。但是微米级别的Cu₂O存在很多问题，例如：微米粉体中的光载流子复合率高；颗粒本身的稳定性差等。然而纳米级别的氧化亚铜在这几方面的性能都得到了显著的改善。因此在本论文中利用Cu⁺的歧化反应制备了粒径只有几个纳米的铜颗粒的胶体；通过铜胶体的氧化制备了性能优异的纳米Cu₂O；通过对各个环节条件的摸索和优化得到了理想的结果。此方法所制备的Cu₂O不仅颗粒较为均匀，且在极性或是非极性溶剂中都可以均匀分散。通过调节反应介质的极性可以得到不同形貌和大小的Cu₂O颗粒，进而获得不同禁带宽度的纳米氧化亚铜，为实现其充分利用可见光提供条件。研究还表明纳米Cu₂O的表面有非常丰富的吸附氧。电化学试验表明在较低的电压下，纳米氧化亚铜能够将氧气还原成为过氧化氢（H₂O₂），有较大的氧还原电流，是一种优良的氧阴极材料。我们利用这一性质结合光照、Fe²⁺等条件，以镍板为基底，在氧化亚铜中加入碳纳米管和粘结剂聚四氟乙烯乳液，组成新的电Fenton系统，用伏安法测得其相对于饱和甘汞电极的氧还原电位，并将之用于活性艳红的降解。结果显示这样的系统能有效的降解活性艳红。在对比试验中可以看出紫外和可见光照对反应都有促进作用。更多还原

【Abstract】 Nanomaterials have become the investigative point in science because of its special structure and superior characters, especially in photo-catalysis field. The rapid progress of nano-technology gives a good opportunity to the application of nano-photocatalysis technology. At present, TiO₂ and ZnO are usually used as photo-catalysts. But they can only be excited by ultraviolet. Costly problems are the obstacle for its industrialization due to the UV light source. Fenton regent has been studied widely because it can generate·HO which has strong oxidizability. But this kind system is not used widely because it costs much H₂O₂ and electrical energy.Cuprous oxide （Cu₂O） is low-cost and can be excited by visible light due to the narrow band gap of 2.1eV. In 1998, Ikeda firstly showed that micron-sized Cu₂O might be employed as a promising catalyst under visible light. But the light generated charge carriers in micron-sized Cu₂O grains are easily lost due to recombination. Reducing Cu₂O grains size can greatly improve the photo-catalysis ability of Cu₂O. We found an extraordinary way to prepare Cu and Cu₂O nano-particles. The copper colloid was successfully formed and subsequently oxidized in ambient air to form stable and easily dispersed cuprous oxide nano-particles. Different morphologies of cuprous oxides were synthesized in different disperse mediums. The products have been characterized and analyzed by X-ray diffraction, Scanning electron microscope and UV-visible absorption spectrum etc. The reaction mechanism has been discussed. Our work also shows that the Cu₂O nano-particles absorb much oxygen on their surface as described in the paragraph of TG-DSC, EDS and XPS observation.The Cu₂O could be a promising material as oxygen-cathode in an electrochemical cell system. So we investigated oxygen-cathode properties of spherical Cu₂O nano-particles. The formation of H₂O₂ has been confirmed by electrochemical method. The experimental results show that the nano-Cu₂O oxygen-cathode is a good catalyst for oxygen reducing reaction. Oxygen can be easily reduced to H₂O₂ in low voltage.We utilized it as new Fenton system to degrade dye-brilliant red X-3B. The results show that this kind of system can effectively degrade dye-brilliant red X-3B. We also found that light can improve the degradation.更多还原