Photoelectrochemical studies on aqueous suspensions of some nanometal oxide/chalcogenide semiconductors for hydrogen production

摘要

Photoproduction of hydrogen was achieved by photolysis of aqueous suspensions of mixed TiO2/V2O5 or CdS/ZnS semiconductor (SC) nanoparticle in phosphate buffers containing [Fe(CN)(6)](4-). Manipulations of the band structure of the SC materials took place by either combining oxides/sulphides in binary mixtures or by modification of the SC surface with an organic semiconductor. Studies show that the bandgap of these mixed materials varied monotonically with the percent composition of the mixture. Furthermore, results show that maximum generation of hydrated electrons by [Fe(CN)(6)](4-) occurred at pH 6. Mixtures of CdS/ZnS showed greater photoactivity than metal oxides TiO2/V2O5. On the other hand, surface-modified CdS or TiO2 gave much better photoreduction than the high percentage composite mixtures. The aqueous nanosystems used in these studies sustained their stability as indicated by the reproducibility of their photocatalytic activities.