博士 / 逢甲大學 / 化學工程學所 / 95 / Using semiconductor photocatalysts for hydrogen production by water splitting have become an innovation and promising technology. The object of this study is to prepare visible-light active photocatalysts with high efficiency in water-splitting for hydrogen production. This thesis contents two parts:
Part I consists of the fabication and characterization of the semiconductor photocatalysts. The simple soft wet-chemistry methods were adopted to prepare all of the photocatalysts. ZnyCd1-yX (X=S, Se) photocatalysts were prepared by coprecipitation method. Anatase-phase TiO2 photocatalysts were synthesized by the liquid phase precipitation method. Rutile-phase TiO2 photocatalysts were prepared by the sol-gel method. The sol-gel method with templates was used to synthesize the hollow TiO2 photocatalysts. XRD, FESEM, EDX, ICP, TEM, 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.
Part II compares the photocatalytic activities of hydrogen production of the prepared ZnyCd1-yX (X=S, Se) and TiO2 photocatalysts from aqueous solutions containing sacrificial reagents of Na2S/K2SO3 under different reaction temperature and different light sources. In the study, the effect of sacrificial reagent concentration on the performance of hydrogen evolution was discussed. The stability and cycling life of the photocatalysts were also examined. The results showed that all of the ZnyCd1-yX (X=S, Se) and TiO2 photocatalysts were able to produce hydrogen gas with nearly 100% purity. Among those photocatalysts, Zn0.5Cd0.5S and Zn0.4Cd0.6S 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 the Zn0.5Cd0.5S photocatalyst. The results indicated that the production rate of hydrogen was 900�慆ol/g.h with the efficiency of 39.39% under ultraviolet irradiation, 850�慆ol/g.h with the efficiency of 4.43% under visible white light irradiation, and 1000�慆ol/g.h with the efficiency of 1.31% under visible yellow light irradiation, respectively. It is also shown that all of the prepared photocatalysts exhibited good stability and cycling life and were easy to reuse.
Conclusively, the prepared ZnyCd1-yX (X=S, Se) photocatalysts have high photocatalytic activities of hydrogen production not only under artificial light sources, but also under direct sun light. However, the prepared TiO2 photocatalysts exhibited good photocatalytic activities of hydrogen production only under UV light irradiation.
| Identifer | oai:union.ndltd.org:TW/095FCU05063026 |
| Date | January 2007 |
| Creators | Chung-chieh Chang, 張忠傑 |
| Contributors | Chih-chieh Chang, 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 | 185 |
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