摻雜鍶於二氧化鈦奈米管對光催化之影響

The Effect of Strontium-Doping in TiO2 Nanotubes on Photocatalytic Activities

簡紹文(Shao-Wen Chien)

指導教授 ： 林明璋

國立交通大學/理學院/分子科學研究所/碩士(2019年)

摘要

本研究採用一步驟的電化學陽極化處理製程，將鍶摻雜到二氧化鈦奈米管上，接著以高溫處理形成anatase phase的二氧化鈦奈米管，最後再進行300°C/3h氫化處理。試片利用XRD分析膜相結構、SEM觀察表面微觀結構、XPS 分析表面化學成份鑑定、UV-VIS吸收光譜測量吸收度及能隙，最後再利用太陽光模擬器(AM 1.5)進行光電流轉換效率測試。
將金屬鈦進行裁切製作成面積0.5*1.5平方公分，白金片做成2*2平方公分，使用交流電供電器做陽極化處理，以鈦片為陽極，白金為陰極，在含有NH4F和不同濃度的Sr(OH)2水溶液，並加入磷酸調整PH值，並施以20V/6h同時參雜鍶和形成二氧化鈦奈米管，接著再震盪清潔及450°C大氣退火，最後進行氫化，其中針對不同陽極化處理過程中的參數及氫化來進行最後試片的元素改質及光電流轉換效率討論。
震盪清潔後的試片相較於未清潔擁有表面較少氧化物及較為平坦，而pH濃度和時間則會有很大的影響奈米鈦管的型態和品質。氫化過後的奈米鈦管可有效減少能隙，並大幅提升光電流轉換效率。參雜鍶的二氧化鈦奈米管在1M KOH 電解質溶液，並照以強度100 mW/cm2的模擬太陽光下(AM1.5)有最佳的光電流轉換效率達0.46%，並在氫化過後其效率提升165%至0.76%，但因實驗裝置的關係，實際上的光強度為85mW/cm2，因此校正氫化過後最佳效率應該為0.87%。

關鍵字

光催化 ； 參雜 ； 鍶

並列摘要

This study investigated the effect of Sr-doping in TiO2 nanotubes (NTs) on water splitting based on photocurrent measurements. The Sr-TiO2 NTs were fabricated by a one-step electrochemical anodization of a titanium foil with an area of 0.5*1.5 cm2. The anodization and Sr-doping were carried out at same time in an aqueous electrolyte containing NH4F and varying concentrations of Sr(OH)2 at different pH’s. After anodization, samples were cleaned by sonification for 30 seconds in DI-water and annealed at 450°C, and finally hydrogenated under 800 Torr H2 atmosphere at 300°C for 3h for efficiency enhancement. All fabricated samples had been characterized with XRD for their crystalline structures, SEM for surface structures, XPS for surface chemical compositions, and UV-VIS absorption spectroscopy for their solar spectral absorption and band gap determination. The photocurrent density and photocurrent conversion efficiency were measured using a solar simulator AM1.5 (100 mW/cm2) illumination. The photocurrent conversion efficiency of Sr-TiO2 NTs was found to be 0.46% and, after hydrogenation, the efficiency was found to improve by 165% to 0.76% which corresponds to the actual efficiency is 0.87% after the 15% incident light intensity correction due to absorption by the electrolyte.

並列關鍵字

photocatalysis ； doping ； strontium

參考文獻

1. Green, M. A.; Keevers, M. J.; Thomas, I.; Lasich, J. B.; Emery, K.; King, R. R., 40% efficient sunlight to electricity conversion. Progress in Photovoltaics: Research and Applications 2015, 23 (6), 685-691.

2. M. L. Perry and T. F. Fuller*, z., A Historical Perspective of Fuel Cell Technology in the 20th Century. The Electrochemical Society 2002.

3. Peighambardoust, S. J.; Rowshanzamir, S.; Amjadi, M., Review of the proton exchange membranes for fuel cell applications. International Journal of Hydrogen Energy 2010, 35 (17), 9349-9384.

4. HOLLAND, L.; LAURENSON, L.; BAKER, P. N.; DAVIS, H. J., Electrochemical Photolysis of Water at a Semiconductor Electrode. NATURE 1972.

5. Anpo, M., Use of visible light. Second-generation titanium oxide photocatalysts prepared by the application of an advanced metal ion-implantation method. Pure Appl. Chem 2000.