氧化鋅奈米柱與奈米材料應用於光電化學分解水

Nanomateriasl modified ZnO nanorod for Photoelectrochemical Water Splitting

陳致凱(Chih Kai Chen)

指導教授 ： 劉如熹

國立臺灣大學/理學院/化學研究所/博士(2014年)

https://doi.org/10.6342/NTU.2014.02248

摘要

石化能源為現今主要之能源來源，然其具儲量漸趨耗竭與伴隨環境汙染問題，發展永續且綠色之能源為各國首要目標。氫氣能量密度高，且由燃料電池能產生電力，具潔淨無汙染之優點。利用光電化學分解水產氫，為氫能利用發展最具潛力之方法。本研究以利用奈米材料設計之奈米微結構之光電極，提升光電化學分解水效率為主要目標。本研究以氧化鋅奈米柱陣列電極為基礎，利用一維之奈米結構，有效增加電子之傳導，提升光電極之光電化學分解水效率。配合不同奈米材料，分成三部分探討奈米結構對光電化學分解水反應之影響。第一部分為利用量子點敏化之氧化鋅奈米柱電極。氧化鋅為寬能隙之半導體材料，其僅可利用紫外光進行光電化學分解水反應。利用碲化鎘與磷化銦量子點調控粒徑大小改變吸收波長，達到有效吸收太陽光，以增加光電化學分解水效率之目的。除增加光吸收，藉由量子點與氧化鋅奈米柱形成之異質結(heterojunction)幫助光生電子-電洞對之分離。第二部分為利用量子點搭配氧化鋅奈米柱形成固融體(solid solution)之結構。藉由量子點之奈米尺寸，有效地達到異原子(heteroatom)之遷移，成功地合成固融體結構，延伸光電極吸光範圍與光電轉換效率。第三部分為利用電漿(plasmon)於光電化學分解水。利用具奈米金修飾之氧化鋅奈米柱陣列為光電極為本實驗之平台，藉由一系列實驗所得之結果辨別電漿子效應所造成之影響。並證實此一提升機制源自於金屬奈米粒子產生之電漿誘導效應。此外，我們亦利用電漿效應提升上轉換奈米粒子之放光效率，利用上轉換奈米粒子、量子點與氧化鋅奈米柱形成之奈米複合系統，成功地利用紅外光進行光電化學分解水反應。
本研究成功利用奈米材料，設計不同奈米微結構之光電極，利用不同之策略，改進光電化學分解水效率，並探討不同策略對光電化學分解水反應之影響。

關鍵字

光電化學分解水 ； 氧化鋅 ； 量子點 ； 金奈米粒子

並列摘要

The fossil fuels drove the development of global economy, it needs to face the problem that source shortage and price and soars. Hydrogen is abundant, pollution-free, high energy density and high efficiency. The photoelectrochemical water splitting could convert the solar energy to hydrogen. Nanotechnology were employed to improve the conversion efficiency of the photoelectrochemical water splitting. In this study, we use the ZnO nanowire-array as the photoelectrode. The one-dimension nanostructure of the ZnO can be a potential solution for raising the light absorption, increasing the surface area and providing electron transport pathway to improve efficiency. Three main approaches will be employed to improve the performance of the photoelectrochemical water splitting. First, using the CdTe and InP quantum dots to sensitize the ZnO photoanode. The sensitization strategy could increase the absorbance range of the light and thus improve the photoactivity of the photoelectrode. Second, using doping strategies to narrow the bandgap of the ZnO. This solid solution structure can performance a better enhancement effect in photoactivity than traditional quantum dots sensitization, and also reveals the hydrogen generation. Third, using gold and silver nanomaterials to decorate on the ZnO to investigate the plamonic enhanced photoelectrochemical water splitting reaction. Both hot electron transfer and electromagnetic field are available for improving the capture of sunlight and collecting of charge carrier.
We had demonstrated that the nano-strucute controlled photoelectrochemical water splitting strategy could enhance the conversion efficiency of the photoelectrochemical water splitting, supporting a new approach to investigating the photoelectrochemical water splitting.

並列關鍵字

photoelectrochemical water splitting ； ZnO ； quantum dots ； gold nanoparticles

參考文獻

[2] Barber, J. “Photosynthetic energy conversion: Natural and artificial” Chem. Soc. Rev. 2009, 38, 185.

[3] van de Krol, R.; Liang, Y. Q.; Schoonman, J. “Solar hydrogen production with nanostructured metal oxides” J. Mater. Chem. 2008, 18, 2311.

[4] Atwater, H. A.; Polman, A. “Plasmonics for improved photovoltaic devices” Nat. Mater. 2010, 9, 205.

[5] Gratzel, M. “Photoelectrochemical cells” Nature 2001, 414, 338.

[6] Yang, F.; Sun, K.; Forrest, S. R. “Efficient solar cells using all-organic nanocrystalline networks” Adv. Mater. 2007, 19, 4166.