這份研究指出高介電材料(二氧化鉿)的最新應用方向，利用其二氧化鉿的缺陷來捕捉載子進而達成光協同作用以利於分解有機汙染物。在實驗過程中，濺鍍陣列式二氧化鉿及二氧化鈦奈米柱來進行研究分析。
因一維材料能有效地增加載子傳遞，故製備二氧化鉿陣列式奈米柱，其彼此間距最大為500nm。而最佳二氧化鉿及二氧化鈦的協同效應為四層結構，二氧化鉿及二氧化鈦的單層厚度分別為375nm及100nm。實驗上發現，在紫外光(30瓦)的照射環境下，濃度為200ppm的樣品經90分鐘後可降解約70%的亞甲基藍水溶液(5ppm)。
為了更完善地此詮釋光協同效應，以二氧化鉿及二氧化鈦的能帶結構圖作為說明，在二氧化鈦產生的光電子會被二氧化鉿奈米柱內的氧(VO2+)缺陷捕捉，而被缺陷的電子會再躍遷到二氧化鉿的導帶。電子捕獲效應也由光致發光圖譜中發現其被捕捉的電子，會在二氧化鉿的氧缺陷(VO2+)產生再結合。除此之外，其光電化學特性也是良好的。

This research reports a novel application of high-k material (HfO2) to photocatalysis for the first time by enabling the defects in HfO2 to trap charge carriers to achieve synergistic photo-decomposition of organic pollutants (methylene blue).
A comprehensive investigation into the fabrication of nanocomposites of HfO2-TiO2 nanorod arrays using reactive sputtering was conducted. Well oriented and a maximum separation of approximately 500 nm of HfO2 nanorods were achieved, which enhanced charge carrier transport along the 1D nanoarchitecture. The optimal coupling between HfO2 and TiO2 for photocatalysis was identified as 4 layered HfO2/TiO2 nanorods with thicknesses of 375nm/100nm for each layer. The sample (200 ppm) was found to photodegrade 70 % of a methylene blue solution (5 ppm) in 90 minutes under 30 W UV irradiation.
The synergistic photocatalytic effect was interpreted using the energy band diagrams of the HfO2-TiO2 system and attributed to the circumstance that the photogenerated electrons in TiO2 were trapped in the gap state of VO2+ in HfO2 nanorods, and then pumped into the conduction band of HfO2. The trapping mechanism was further analyzed by performing the measurement of photoluminescence spectroscopy. Another interesting application of the system to a photoelectrochemical reaction was demonstrated as well.

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