罗丹明B在TiO2薄膜和P-25涂层催化下光反应的比较

半导体光催化剂尤其是TiO₂由于表面的光生空穴具有很强的氧化能力^[1-2],能够完全降解有机物,在环境治理方面具有潜在的应用前景,因而日益引起人们的关注.目前,利用胶体溶液和颗粒悬浮体系光催化降解有机污染物的研究已经开展得十分广泛^[3-5].但是,从实用的角度来考虑,这一体系存在许多缺点,如反应后催化剂难于分离,颗粒不适宜作循环体系的处理等等,因此催化剂的固定日益迫切.为解决这一问题,近来已经有许多人在固定粉末催化剂以及制备催化剂薄膜方面^[6-8]进行了探索和尝试,但尚未得到理想的结果.因而发展高效固定化的催化剂仍然是极为重要的,同时对于薄膜催化机理的深入探讨也有利于在制备过程中有目的地提高膜的催化活性.

COMPARISON OF PHOTOREACTIONS OF RHODAMINE B CATALYZED BY A TiO2 THIN FILM AND A DEGUSSA P-25 COATED FILM

Transparent anatase TiO₂ thin film was prepared on glass substrates by dip coating method. The photocatalytic properties of the film was assessed by measuring the photodegradative oxidation of Rhodamine B in aqueous solution and compared with a Degussa P-25 coated film. This film showed much higher photoactivity than P-25 coated film initially because the photoreactive mechanisms assisted by the two kinds of films are obviously different: fast N-de-ethylation and further degradation accompanied the degradation of Rhodamine B catalyzed by a TiO₂ thin film, whereas only degradative reaction took place in a P-25 coated film existed.