金電漿子奈米粒子披覆於三氧化鉬複合二氧化鈦奈米管陣列之核殼結構應用於增強光催化反應效率

Au-Plasmonic Nanoparticles Enhanced Photocatalytic Activities on Photoelectrode of MoO_3 Coated TiO_2 Nanotubes

洪緯璿(Wei-Hsuan Hung) ； 李佳叡(Chia-Jui Li) ； 林芳玟(Fang-Wen Lin) ； 林均翰(Chun-Han Lin)

《真空科技》 29卷4期 (2016/12) Pp. 29-35

摘要

現今最常見的光觸媒材料為二氧化鈦(TiO_2)，其擁有製備簡單、低毒性、化學穩定性高等優點，但由於其能隙過大導致僅能受紫外光區之光子來激發電子- 電洞對分離，故有許多科學家針對TiO_2 進行改質，而利用雙金屬氧化物半導體是目前常見的改質方法之一。在此將針對二氧化鈦(TiO_2) 與三氧化鉬(MoO_3) 兩種金屬氧化物來進行探討，由於TiO_2 與MoO_3 之間的異質界面結構，光生電子會由TiO_2 傳導至MoO_3，而光生電洞會由MoO_3 傳導至TiO_2，透過此機制更能夠增加光生電子- 電洞對之分離率，進而提升光催化分解水之效率。為了再次提升光催化反應效率，亦加入了金電漿子奈米粒子，利用金屬表面產生之局部表面電漿子共振效應(Localized surface plasmon resonance, LSPR) 來進一步增強光催化反應效率。本研究利用兩階段陽極氧化法以及簡易之水熱法來製備TiO_2 與MoO_3 並複合成核殼結構光電極，並藉由場發射掃描式電子顯微鏡(FE-SEM)、X 光光電子能譜儀(XPS) 對其進行初步特性分析。

關鍵字

金屬氧化物 ； 核殼結構 ； 電漿子金屬奈米粒子 ； 光催化反應

並列摘要

Although TiO_2 used to be a commonly used material for photocatalysis reaction, due to its wide band-gap (3.2 eV), it can solely absorb the ultraviolet light of the solar spectrum, which accounts for only 4% of total sunlight. It can only separate charge carriers under UV light irradiation, which greatly limiting its practical applications. Modification of TiO_2 have been more important in research of photocatalysis reactions. Using two metal oxide semiconductors is one of the most common method. When MoO_3 and TiO_2 contacts forming heterogeneous interface, photogenerated electrons transfer from TiO_2 to MoO_3 while holes transfer from MoO3 to TiO_2. It can efficiently separate the photogenerated electron-hole pairs and promote the photocatalysis efficiency. This additional photocurrent enhancement is attributed to the strong near-field and light scattering effects from the plasmonic Ag NPs. In our work, we report the fabrication of MoO_3-coated TiO_2 nanotubes heterostructures with 3D hierarchical configuration by a two-step anodic oxidation and a facile hydrothermal method. Such a 3D hierarchical structure consists of a core of TiO_2 nanotubes and shell of MoO_3 (referred to as TNTs@MoO_3). Finally, we characterized by field emission scanning electron microscope (FE-SEM), X-ray photoelecton spectroscopy (XPS).

並列關鍵字

Metal Oxide ； Core-shell Structure ； Plasmonic NPs ； Photocatalytic Reaction