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【答案】应助回帖
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tata880214(金币+200, 翻译EPI+1): 什么时候我才能达到这样的水平，是不是要多看文献，谢谢拉 2011-07-21 15:04:35
Mally89(金币+2): 感谢应助！~欢迎常来！~ 2011-07-23 21:28:39
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Fig.3 The UV - visible absorption spectra of three gold catalyst and their supports According to the literature that，the gold particles can absorb visible light because of its surface plasmon nature. In order to understand further the prepared different systems of the nature of gold catalysts, UV-visible absorption characterization was carried out. From UV-Vis map we found that, before gold was supported, whether it is ZrO2, Al2O3 or TiO2 only in the UV (200-400 nm) range had partial absorption, there was no absorption at visible light region （λ> 400 nm）. The performance of these oxides has changed When gold particles were supported in the surface of these oxides supports. From UV-visible spectrum can be clearly seen that the supported gold catalyst had a wide range of new peaks at 550 nm. Kowalska et al [19] proved that it was due to surface plasmon resonance. When the electric field intensity of incident light and the gold particles in the shock of the conduction band electron coupling occurs, will lead to a increase of electric field intensity on gold surface, so the gold nanoparticles can absorb 520-550 nm visible light [20]. At the same time, surface plasmon effects produced by different sizes of golds are different [21-22], absorption range of visible light will be different. Comparison of the UV-Vis spectra of three different gold catalysts , we can see that Au/TiO2 the widest absorption peak range at 550nm, and the strongest intensity of the absorption of visible light. Reported [23], the gold particles of the plasma coupling was affected by shape, size, distance between the particles of gold particles，and so on, and the larger gold particles, the stronger the absorption of visible light [24]. In addition, UV-Vis spectra also showed that, Au/TiO2, Au/ZrO2 has a high ability to absorb light. EDS results showed that support of Au/TiO2, Au/ZrO2 and Au Au/Al2O3 catalyst were 8.23wt%, 8.37wt%, 3.12wt%. Therefore, the ability to absorb light of gold catalysts was related to support.The more supported gold particles, the prepared gold catalysts had stronger intensity of absorption of light. |
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