應用於水裂解產氫之鉭酸鈉光觸媒研究

本研究之NaTaO3:La光觸媒是以Ta2O5、Na2CO3與La2O3為前驅物，分別以固態反應法(SSRM)與熔鹽法(MSSM)製備，並同時負載NiO以製備應用於水裂解反應產氫之高性能光觸媒。所得之光觸媒分別以X-ray繞射儀 (XRD) 、UV-Vis光譜儀、掃描式電子顯微鏡(SEM) 、比表面積分析儀 (BET)等分析其性質。由XRD結果可知由固態反應法與熔鹽法所製備之觸媒皆有相同結構和組成。由UV-Vis結果得知由固態反應法或熔鹽法製備之光觸媒皆以NiO/NaTaO3:La(2%)有最佳吸光值。由SEM可觀察固態反應與熔鹽法所製備之觸媒皆有相同表面結構。光觸媒活性測試是在批式反應器中將純水或10%甲醇水溶液以450W高壓汞弧燈紫外光照射進行水裂解反應產氫氣，並以氣相層析儀(GC)分析其產物組成。本實驗將比較由不同製備法所得之光觸媒性質，由研究結果可知，使用熔鹽法可減少NaTaO3:La觸媒的製備時間及增加反應活性。最佳水裂解產氫條件為使用NiO/NaTaO3:La(2%)於10%甲醇水溶液，其最高氫氣產生速率為30204μmole/10hr(約74ml/hr)。

關鍵字

光觸媒、鉭酸鈉、水分解、氫氣

並列摘要

In this research, the photocatalyst NaTaO3:La in prepared with Ta2O3、Na2CO3 and La2O3 as the precursor by using respectively the solid state reaction method(SSRM) and the molten salt method(MSSM) and is carried with NiO simultaneously so as to prepare the photocatalyst of high performance to be applied in the water splitting reaction to produce hydrogen. The properties of the photocatalysts obtained are analyzed respectively with X-ary diffraction analyzer(XRD)、UV-Vis spectrum analyzer、Scanning electronic-microscope(SEM)、Brunauer-Emmett-Teller Surface Measurement(BET).From XRD results it can be known that the catalysts which are prepared by the solid state reaction method and the molten salt method all have the same structures and compositions. From Uv-Vis results it can be known that among the photocatalysts which are prepared with the solid state reaction method and the molten salt reaction method, NiO/NaTaO3:La(2%) processes the highest absorbing value. From SEM it can be observed that the catalysts prepared with the solid state reaction method and the molten salt method all have the same surface structures. The activities of the photocatalysts are measured out in measurement batch reactor and the water-splitting reaction is proceeded with pure water or 10% methanol aqueous solution by the irradiation of ultraviolet light and the 450W high pressure mercury arc light and the compositions of the reaction products are analyzed with the gas chromatograph(GC).In this experiment, comparisons are made for the properties of photocatalysts prepared from various methods,form the research result it can be known that by using the molten salt method, preparation time of the catalyst NaTaO3:La can be decreased and the reaction activity can be increased. The best condition of water splitting for producing hydrogen is to apply NiO/NaTiO3:La(2%) in 10% methanol aqueous solution and the highest hydrogen producing rate is 30204μmole/ h.g.cat.10hr(about 74ml/ hr.g.cat).

並列關鍵字

Photocatalyst、NaTaO3、Water splitting、hydrogen

參考文獻

[1].H. Kato, A. Kudo,” Photocatalytic water splitting into H2 and O2 over various tantalite photocatalysts” Catalysis Today, 78 (2003) 561-569.

[2].Hideki Kato, Kiyotaka Asakura, and Akihiko Kudo,”Highly Efficient Water Splitting into H2 and O2 Over Lanthanum-Doped NaTaO3 Photocatalysts With High Crystallinity and Surface Nanostructure, J.AM.CHEM.SOC.2003,125,3082-3089

[4].A.V. Gorokhovsky, J. I. Escalante-Garcia, T. Sanchez-Monjaras, C. A.Gutierrez-Chacarria” Synthesis of potassium polytitanate precursors by treatment of TiO2 with molten mixture of KNO3 and KOH”,Journal of the European Ceramic Society 24 (2004) 3541-3546

[5].HideKi Kato and Akihiko Kudo”Water Splitting into H2 and O2 on Alkali Tantalate Photocatalysts ATaO3(A =Li,Na,and K)” Journal physical Chemical.B 2001,105,4285-4292

[6].Meldrum,L.A. Boatner, W. J. Weber, R. C. Ewong,”Amorphization and recrystallization of the ABO3oxides”,Journal of Nuclear Materials 300 (2002) 242-254

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應用於水裂解產氫之鉭酸鈉光觸媒研究

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