金電漿子奈米粒子披覆於二硫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

Deposited Au-Plasmonic Nanoparticles on Thin Amorphous MoS_2 Nanosheets Shell with TiO_2 Nanotubes for Enhanced Photocatalytic Activities

洪緯璿(W. H. Hung) ； 李佳叡(C. J. Li) ； 蘇政一(C. Y. Su) ； 陳明雄(M. H. Chen) ； 楊欽儒(C. J. Yang) ； 林芳玟(F. W. Lin) ； 林均翰(C. H. Lin) ； 蔡奇陸(C. L. Tsai)

《真空科技》 29卷1期 (2016/03) Pp. 39-44

摘要

綜觀現今最常被使用之光觸媒材料為TiO_2，但由於其能隙過大(3.2 eV)，只能受到紫外光區之光子激發進而產生電子－電洞對分離，而對於太陽全光譜之光子吸收更僅有4 % 的利用率，故許多學者將改質TiO_2列為重要之研究方向。二硫化鉬(Molybdenum Disulfi de, MoS_2)為近幾年來研究光能轉換系統之新穎材料，而我們已成功製備出層狀結構之二硫化鉬，其因能隙較小，僅需可見光區之光子激發即可使電子- 電洞對分離之優點，故可作為催化劑增加光觸媒材料(如：TiO_2)於可見光波段之吸收效率，而內部之層狀結構亦能提供一個電子傳輸之通道，避免光觸媒材料之激發電子發生再結合(Recombination)，透過此機制，能使複合光觸媒材料對於較低能量光子進行吸收以增強可見光區光子利用率，並同時大幅降低光生電子電洞對再結合機率，更能顯著的提升光催化分解水之效率。本研究中，我們已經利用兩階段陽極氧化法及簡易之水熱法製備出二氧化鈦奈米管－二硫化鉬複合奈米核殼結構，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)以及吸收光譜量測系統(UV/VisSpectrometer)對其進行初步特性分析。

關鍵字

二維材料 ； 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 photocatalytic reaction, due to its band gap is too large (3.2 eV), it can only separate charge carriers under ultraviolet light irradiation. However, TiO_2 can solely absorb the UV light, which accounts for only 4 % of the total sunlight, thus greatly limiting its practical applications. Surface modifi cation of TiO_2 have been more important in research of photocatalysis. Among these 2D layered materials, MoS_2, composed of Mo atoms sandwiched between two layers of hexagonally close-packed sulfur atoms, can be exfoliated to give single- or few- layer nanosheets, which are particularly important for sensing, lithium battery, phototransistor and photocatalytic hydrogen production applications. We have successfully fabricated MoS_2 with layered internal structure. Because of narrow band gap, it can have higher absorption effi ciency under visible light. Also, layered structure of MoS_2 provide the photogenerated electrons in the conduction band of TiO_2 can be transferred to MoS_2 nanosheets, which act as a conductive electron transport ＂highway＂, and then suppress photogenerated electrons-hole pairs recombination rate. Based on layered structure of MoS_2, suppression of charge recombination can promote the photocatalytic efficiency. In our work, we report the fabrication of few-layer MoS_2 nanosheetcoated 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 MoS2 nanosheets (referred to as TNT@MoS2). Finally, we characterized by field emission scanning electron microscope, X-ray photoelecton spectroscopy, and UV/Vis Spectrometer.

並列關鍵字

Two Dimension Material ； Core-Shell Structure ； Plasmonic Nanoparticles ； Photocatalytic Activity