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通过阳极氧化法在金属钛表面制备了TiO2纳米管阵列涂层(TiO2 nanotube array,TNT),并通过改变其形貌和相态探索TNT涂层光催化反应的机理。研究表明TNT涂层光催化降解有机物的机理是依靠光生空穴与氧化剂生成的羟基自由基来氧化有机物中的基团。此外涂层表面的F离子残留量对TNT涂层的光催化性能有一定的影响,F离子残留量越少,纳米管的光催化活性越高,这是由于在光照条件下,带有负电的F离子易于和带正电的光生空穴发生反应,同时由于F离子的残留使纳米管中出现了Ti3+,从而降低了光生电子的数量。低温退火处理条件下,纳米管的形貌基本上没有改变,影响半导体材料性能的主因是相态变化,锐钛矿占主体的混晶结构能够有效促进光生电子-空穴对的分离和传输,从而提高光催化性能。
TiO2 nanotube array (TNT) was prepared on the surface of titanium by anodic oxidation. The mechanism of photocatalytic reaction of TNT was explored by changing its morphology and phase. The research shows that the mechanism of photocatalytic degradation of organic compounds by TNT coatings is to oxidize organic groups by hydroxyl radicals generated by photogenerated holes and oxidants. In addition, the residual amount of F ions on the coating surface has some influence on the photocatalytic performance of the TNT coating. The smaller the residual amount of F ions, the higher the photocatalytic activity of the nanotubes due to the negative charge F ions tend to react with positively charged photogenerated holes, and at the same time Ti3 + appears in the nanotubes due to the residual F ions, thus reducing the number of photogenerated electrons. The morphologies of the nanotubes are basically unchanged under the conditions of low temperature annealing. The main factors affecting the performance of the semiconductor materials are the phase changes. The mixed crystal structure of anatase mainly promotes the separation and transport of photogenerated electron-hole pairs, Thus improving photocatalytic performance.