二氧化鈦奈米管在可見光/紫外光分解水的效應

Abstract

本實驗主要研究利用電化學方法合成二氧化鈦奈米管，並摻雜了碳元素在二氧化鈦奈米管中，經由水分解系統分別量測可見光及紫外光效率，發現高密度排列的奈米管及參雜碳元素都可以明顯的增加反應效率，且紫外光區電流及水分解效率都較可見光區好，而我們也經由SEM圖譜、XRD圖譜、及不同條件的二氧化鈦奈米管的水分解效率了解一些二氧化鈦奈米管的物理特性，可以發現奈米管電解液組成為10%的DI water + 0.5% NH4F + 89.5%的glycerol，鍛燒溫度為500℃，水分解的電解液為1M KOH效果最佳，水分解效率在紫外光區(320±70nm)可達28%，但在可見光區(520±30nm)卻只有0.16%，並不如Misra在J. Phys. Chem. C 2007[4]所發表的結果，可是在可見光區的低效率卻與Murphy[44]最近的結果相似。最後我們也利用XPS、IPCE及反射式吸收光譜對可見光部分進行詳細討論。

In this research, we study TiO2 (TiO2-xCx) nanotubes synthesized by the application of sonoelectrochemistry. We obtained vertically grown TiO2-xCx nanotubes arrays with high aspect ratios for water splitting in the visible and ultraviolet light regions. The best electrolyte for anodization was found to be 10% DI water + 0.5%NH4F +89.5% glycerol with the annealing temperature at 500℃. The observed efficiency results clearly from TiO2 nanotubes, and the ultraviolet light region showed a much greater efficiency than the visible region. The properties of the synthesized TiO2-xCx nanotubes have been investigated with SEM, XRD and different electrolytes for water splitting. The best electrolyte for water splitting is 1M KOH solution. Finally we study in detail in the visible region using TiO2-xCx characterized by XPS、IPCE and reflection-absorption spectroscopy. The low efficiency observed in the region disagrees with the 8.5% efficiency reported by Misra and coworkers(J. Phys. Chem. C 2007, 111, 8677-8685), but is consistent with the result of Murphy (Solar Energy Materials＆Solar Cells, 92, 2008, 363-367).