阵列型TiO2纳米管光催化降解VOCs性能

摘要

通过二次阳极氧化电化学方法制备纳米孔/纳米管复合结构的阵列型TiO2纳米管（2-step TiO2 NTs），实验证明这种结构的TiO2 NTs对大气中的挥发性有机化合物（volatile organic compounds，VOCs）有着十分优异的降解效果。本文通过气态甲醇的光催化降解来评估比较一次氧化生成的TiO2纳米管（1-step TiO2 NTs）和2-step TiO2 NTs的催化效果。实验结果表明，二次阳极氧化电化学方法所生成的TiO2 NTs的纳米结构对光致电荷的产生有着十分重要的推动作用。之所以2-step TiO2 NTs的纳米孔/纳米管复合结构能够显著提高VOCs的降解效率，是由于这种特殊的结构能够更加有利于电子的传递，同时能够有效地抑制光生电子和空穴的复合。最后，通过实验数据阐述了2-step TiO2 NTs光催化活性的增强机理，这种新结构显示出更小的带隙、更高效的光生电子/空穴分离效率和VOCs降解性能。%The top-porous/bottom-tubular TiO2 nanotube arrays(TiO2 NTs)were preparedvia a facile two-step anodization method for efficient decomposition of VOCs(volatile organic compounds)in air. The gas phase photocatalytic activity of conventional 1-step TiO2 NTs and top-porous/bottom-tubular TiO2 NTs were estimated by decomposing of methanol vapor. The results show that,a heterojunction structure formed in top-porous/bottom-tubular TiO2 NTs composite plays an important role in the dynamics of photogenerated charges. The top-porous/bottom-tubular TiO2 NTs combined structure significantly enhanced the photocatalytic activity of decomposition of VOCs,which is due to the enhanced electrons transfer and the reduce of the recombination of photogenerated electrons and holes. The mechanism for the enhancement of the photocatalytic activity of top-porous/bottom-tubular TiO2 NTs was discussed according to our experimental results.