乙酸钠、草酸钠、酒石酸钾在三氧化钨-水体系中光生自由基的研究

当分散在溶液中的TiO_2、znO、CdS、WO_3等多相体系受到光照时,固态的半导体物质吸收光子后会产生电子-空穴对,它们在半导体界面上与周围介质反应,可能以各种方式进行电荷转移而形成不同的活泼中间体,引起人们对发生在半导体粉末上的光化学过程的关注。

ESR STUDY ON PHOTOGENERATED RADICALS IN AQUEOUS DISPERSIONS OF TUNGSTEN OXIDE CONTAINING SODIUM ACETATE, SODIUM OXALATE AND POTASSIUM TARTRATE

The free radical intermediates produced under the illumination of aqueous dispersions of tungten oxide were detected by ESR combined with the technique of spin trapping.When solutions contained sodium acetate were irradiated, the CH3 radical was detected. Whereas in systems containing sodium oxalate the CO2- radical was obse-rved. In systems containing potassium tartrate, the OH, CO2- and -OOCCOHCH-OHCOO- radicals were identified.Experiments showed that irradiation of aqueous WO3 dispersions gives rise to the formation of OH radicals. If appropriate substances are present, various other radicals can be generated as well. These are produced either by reaction with theOH radicals, or direct transfer of charge from the bands of the semiconducting material.