Please use this identifier to cite or link to this item:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/62430
Title: | 硫化鎘奈米鈦管以可見光催化甲酸溶液之產氫研究 Production of Hydrogen from Water Using Formic Acid and CdS/Titanate Nanotubes with Visible Light Irradiation |
Authors: | Yi-Chun Lai 賴宜君 |
Advisor: | 駱尚廉 |
Keyword: | 甲酸,二氧化鈦,奈米鈦管,氧化鈦奈米管,硫化鎘,鉑,氫氣, Hydrogen,Photocatalyst,Titanium dioxide,Titanium nanotubes,Cadium sulfide,Platinum,Formic acid, |
Publication Year : | 2013 |
Degree: | 碩士 |
Abstract: | 石油燃料的枯竭、全球暖化的加劇,研發與推動新能源技術一刻不容緩。在
眾多的再生能源當中,氫能最備受矚目,先進國家視其為最具潛力的明星能源產 業,近年來,皆積極投入大量的研究資源於其中。氫能源擁有許多優勢,其不具 毒性、為宇宙中最單純的元素,除此之外,最重要的是,氫能能量密度為石油燃 料的三倍,且水為唯一反應產物。 光觸媒是相當具有發展潛力的綠色環保材料,近年來,亦有不少研究利用光 觸媒分解水產氫。本研究為提升現有二氧化鈦光觸媒之水解產氫效率,選用改質 之奈米鈦管於甲酸溶液中進行產氫研究。研究指出,甲酸能夠有效地擔任電洞捕 捉劑,延緩電子電洞對再結合,而微波水熱法製成之奈米鈦管因擁有特殊的管狀 外形、材料分布均勻、與高比表面積的特性,相對於二氧化鈦,能夠披覆上較高 比例的共觸媒,有利於增加產氫量。硫化鎘與貴重金屬鉑為本研究披覆上奈米鈦 管之共觸媒,硫化鎘能夠有效地移轉吸收光譜至可見光區,而鉑可以提高觸媒活 性、延長電子電洞對分離的生命週期。 實驗結果顯示,常溫下以 150W 的可見光催化 10 vol%甲酸溶液,利用光沉 積法披覆上鉑之 1wt%Pt/CdS/TNTs 擁有最好的產氫效率,達 640 μmol.g -1h-1,其次為純 CdS/TNTs,效率達 363 μmol.g-1h-1,而使用CdS/TiO2 的產氫率只有123 μmol.g-1h-1。輔以物化分析結果顯示,以 TNTs 作為載體時,能夠披覆上較高比例之共觸媒,且 TNTs 可作為犧牲材料,包覆金屬於管狀中,因此不易被空氣氧化。 至於動力操作實驗中,參數包括溫度、pH 值的調控。發現 CdS/TNTs 隨著 反應環境溫度上升,產氫率也隨之上升,溫度 45℃時,氫氣生成量為 478mol.IIIg-1h-1,是常溫的 1.3 倍,然而 CdS/TiO2 即使溫度改變,其產氫效率仍然沒變,因此可知,;反應環境酸鹼值的改變顯示出,離子態的甲酸要比分子態的甲酸分子容易與觸媒接觸、產生反應。因此,高溫度、低 pH 值的反應條件有助於提升CdS/TNTs 光觸媒之產氫效率。 披覆上貴重金屬鉑的方法有很多,本實驗分別使用熱含浸法與光沉積法試驗 之。熱含浸法雖簡易、方便,但合成的鉑易在觸媒表面形成不均勻的大顆粒,遮 蔽效應反而使得觸媒的活性下降;相對地,光沉積法則可披覆上顆粒均勻、細緻 的金屬粒子於觸媒表面。因此,利用光沉積法披覆鉑於觸媒上,為本研究較適宜 的方法。 Hydrogen gas is one of the most promising renewable energy sources and the final product of hydrogen combustion is nothing but water. Recently, many researches have been conducted to produce hydrogen from water using catalytic photosynthesis. The research investigated the rates of hydrogen production from water using formic acid and visible light with several types of catalysts (CdS/Titanate nanotubes,CdS/TiO2, Pt/CdS/TNTs by photodeposition, Pt/CdS/TiO2 by thermal impregnation,and Pt/CdS/TNTs by thermal impregnation). Due to the specific geometry of TNTs, more CdS can be attached onto the TNTs surface than to with that of TiO2’s, so the yield of hydrogen is much higher with CdS/TNTs than CdS/TiO2 under 150W visible light. The hydrogen production with CdS/TNTs achieved 363μmol.g-1 h-1, which is about three times higher than that with CdS/TiO2’s. As the temperature elevated to 45℃ from 25℃, the H2 production with CdS/TNTs reached 478μmol.g-1h-1, while the H2 production with CdS/TiO2 did not show much change with temperature. Lower pH has a better affinity to formic acid will mainly be in an ionic form. Consequently, lower pH helps produce enhanced H2 production. Moreover, coating of platinum onto the photocatalysts could further promote the reaction. Results showed that 1wt%Pt/CdS/TNTs made by photodeposition method had the best hydrogen production, 640μmol.g-1h-1 under ambient condition. Surface properties of the photocatalysts was categorized using scanning electron microscopy/energy dispersive X-ray (SEM/EDX), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopic(XPS). |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/62430 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 環境工程學研究所 |
Files in This Item:
File | Size | Format | |
---|---|---|---|
ntu-102-1.pdf Restricted Access | 5.22 MB | Adobe PDF |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.