| 1. | Titanium dioxide is a semi - conductor with wide band gap , and its photocatalysis operates only when it is irradiated under the ultraviolet radiation of sunlight , and also , the electron hole of tio _ 2 has very high reunited rate 但由于tio _ 2为宽禁带半导体,对太阳光的利用仅局限于紫外部分,并且tio _ 2的光生电子空穴复合几率很高。 |