碩士 / 逢甲大學 / 化學工程學所 / 97 / Using semiconductor photocatalysts for hydrogen production by water splitting have become an innovative and promising technology. The object of this study is to prepare visible-light active photocatalysts with high efficiency in water-splitting for hydrogen production.
The simple soft wet-chemistry methods were adopted to prepare all photocatalysts. ZnyCd1-yS photocatalysts were prepared by the coprecipitation method. The photocatalytic activities of hydrogen production of the prepared ZnyCd1-yS photocatalysts from aqueous solutions containing sacrificial reagents of Na2S/K2SO3 under different reaction temperature and different light sources. The results suggest that the noble metal on the ZnyCd1-yS photocatalysts enhance the charge separation of the excited electron-hole pairs in the ZnyCd1-yS photocatalysts. In the study, Nobel metal nanoparticles have been formed on the surface of ZnyCd1-yS via photoreduction method .The effect of sacrificial reagent concentration on the performance of hydrogen evolution and different noble metals are discussed. In addition to studying different noble metals , concentrations of the noble metal precursor solutions are also discussed. The stability and cycling life of the photocatalysts were also examined. XRD, FESEM, EDX, XRF, BET, and UV-Vis were used to examine the morphologies and properties of the photocatalysts. The photocatalytic activities of the photocatalysts were evaluated by their degradation of methylene orange.
The noble metal on the ZnyCd1-yS photocatalysts were able to produce hydrogen gas with nearly 100% purity. Among those photocatalysts, Pt0.015/Zn0.5Cd0.5S exhibited the best performance of hydrogen production. Under three different temperatures, the production rate and photo-efficiency of hydrogen evolution were in the order of 55℃＞70℃＞30℃. With three different light sources at 50℃, the best results of the hydrogen production were obtained by thePt0.015/Zn0.5Cd0.5S photocatalyst. The results indicated that the production rate of hydrogen was 989.6�慆ol/g．h with the efficiency of 1.48% under visible white light irradiation, and 1429.4�慆ol/g．h with the efficiency of 0.27% under visible yellow light irradiation, respectively. It is also shown that all prepared photocatalysts exhibited good stability and cycling life and were easy to reuse.
Conclusively, the prepared ZnyCd1-yS photocatalysts and the noble metal on the ZnyCd1-yS photocatalysts have high photocatalytic activities of hydrogen production not only under artificial light sources, but also under direct sun light.
| Identifer | oai:union.ndltd.org:TW/097FCU05063014 |
| Date | January 2009 |
| Creators | Hsiao-Han Lin, 林曉涵 |
| Contributors | none, 詹志潔 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 148 |
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