碳/铬掺杂二氧化钛粉体的制备与表征#
 

摘要：采用球磨法合成碳、铬掺杂的氧化钛材料，碳、铬掺杂用于调节材料的氧空位缺陷度。应用X 射线衍射仪、紫外—可见分光光度计、荧光分光光度计等表征手段测试了样品的结构和光学性能。结果表明：碳、铬掺杂使材料的氧空位缺陷发生不同程度的改变。此外，对碳、铬掺杂的二氧化钛的可见光活性的来源作了相应解释。
 

关键词：复合材料；碳；铬；二氧化钛；氧空位；红移

0 引言
二氧化钛（TiO2）具有优越的光催化及亲水性能，在废水处理、空气净化、杀菌、防雾、自清洁等领域显示出广阔的潜在应用前景[1-3]。然而，TiO2 的带隙较宽，光响应范围局限于波长小于或等于387 nm 的紫外区，太阳能利用率低。光生电子—空穴易复合，寿命短，严重制约了TiO2 在光催化技术和亲水性能方面的广泛应用[4-5]。因此，为了提高TiO2 的光催化活性，改善亲水性，各国学者从制备技术、掺杂改性到催化、亲水机理对TiO2基半导体材料作了深入研究。
 

大量研究表明，TiO2 的光催化率和亲水性与氧空位缺陷度紧密相关。Kuznetson 等[6]提出非金属掺杂TiO2 的可见光催化活性源于氧空位缺陷引起的F 色心的出现。Meng 等[7]指出TiO2 表面氧空位的增加有助于增强光吸收，从而提高燃料敏化太阳能电池的光电转换效率。Serpone[8]证实了掺杂TiO2吸收边的红移与氧空位缺陷有关。Sangpour 等[9]采用射频反应磁控溅射制备了M-TiO2(M=Au, Ag, Cu) 薄膜，发现Cu-TiO2 由于更多的Ti3+氧空位的存在，对亚甲基蓝有最高的光催化降解率。Meng 等[10]应用射频磁控溅射分别在硅和石英基片上沉积了不同银含量的TiO2 纳米结构薄膜，发现薄膜的亲水性能随银含量的增加先增后减，最适宜的银含量为5.0vol%，源于表面Ti3+活性中心使薄膜表面的电子-空穴有效分离。
 

本文以含有Ti7O13缺陷态的TiO2为原料，采用球磨法对原材料进行碳或铬的掺杂改性。相关测试结果表明，碳或铬掺杂实现了对氧空位缺陷的可控性调节，扩展了氧化钛的光活性响应范围。这对氧化钛光催化及亲水性能的改进尤为重要，有利于满足氧化钛工业应用领域的不同需求。

3 结论
碳或铬掺杂样品光致发光谱强度的差异，表明了不同掺杂样品中氧空位缺陷的改变。通过碳或铬的选择性掺杂，氧化钛材料的氧空位缺陷实现了可控性调节。碳、铬掺杂样品在可见光波长范围内吸收谱强度的增加，源于不同态间电子跃迁和氧空位缺陷态的形成。
 

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