镧铁共掺杂二氧化钛纳米线阵列的可见光催化性能

VISIBLE PHOTOCATALYTIC ACTIVITY OF TITANIA NANOWIRE ARRAYS CO-DOPED WITH LANTHANUM AND IRON

采用溶胶-电泳沉积技术,在多孔氧化铝模板中合成了二氧化钛(TiO_2)纳米线阵列结构。研究了La^(3+)/Fe^(3+)共掺杂对TiO_2纳米线可见光催化性能的影响,并分别与La^(3+),Fe^(3+)单掺杂TiO_2纳米线可见光催化性能进行了比较。结果表明:与La^(3+),Fe^(3+)单掺杂TiO_2纳米线相比,La^(3+)/Fe^(3+)共掺杂TiO_2纳米线具有更高的可见光催化活性,光照4h对甲基橙的降解率就达到了90%以上,大幅度提高了TiO_2的可见光催化活性,这是因为2种不同体系离子的协同作用,不仅有效抑制了光生电子和空穴的复合,而且明显降低了TiO_2的禁带宽度,由3.24降低到2.38。研究还表明:TiO_2纳米线阵列极大的比表面积以及表面特有的性质和结构是掺杂改性TiO_2纳米线具有较高可见光催化活性的重要因素。

Titania（TiO2） nanowire arrays were synthesized in highly ordered porous anodic alumina （PAA） template by the sol-gel method. The visible photocatalytic activity of La^3＋/Fe^3＋/TiO2 nanowires was studied. The results indicate that La^3＋/Fe^3＋/TiO2 nanowires have apparent higher visible photocatalytic activity than that of La^3＋/TiO2 and Fe^3＋/TiO2. Under the condition of 4 h irradiation, the degradation ratio of methyl orange exceeds 90%. The visible photocatalytic activity is highly improved. This is attributed to the coaction of La^3＋ and Fe^3＋, which not only can effectively inhibit the recombination ofphotoinduced electrons and holes but also can narrow the band gap of TiO2 from 3.24 to 2.38. The results also show that the high specific surface area and special characteristics of the surface play a big role in enhancing the visible photocatalytic activity of TiO2 modified by metal ions.