應用於水裂解產氫之高性能NiO/K2Ti6O13光觸媒研究

High performance of NiO/K2Ti6O13 Photocatalysts for Water-splitting to Produce Hydrogen

廖為坤(Wei-Kun Liao)

指導教授 ： 陳炎輝

大同大學/工程學院/化學工程學系所/碩士(2007年)

摘要

本研究之K2TinO2n+1 光觸媒是以K2CO3 與溶膠凝膠法所製備之TiO2為前驅物在不同的莫爾比下混合，並利用固態反應法分別煅燒10 小時、24 小時和50 小時後得到。所製備之光觸媒接著將負載 NiO 以得到NiO/K2TinO2n+1。並取其最佳光觸媒活性產氫量觸媒摻入(doping) Rh 離子。觸媒分別利用X 射線繞射儀(XRD)，UV-VIS 光譜儀，掃瞄式電子
顯微鏡(SEM)，比表面積分析儀(BET)，分析光觸媒的特性。由XRD 結果可得知觸媒的結晶結構為K2Ti6O13。此外UV-Vis 可得K2Ti6O13 光觸媒掺入Rh 離子在可見光範圍具有強的吸光能力。SEM 可得知觸媒表面形態為細長纖維鬚狀。BET 可知莫爾比值為6，鍛燒24 小時後的觸媒其表面積最大。K2Ti6O13 光觸媒活性是用批式反應器分別將純水與10%甲醇水溶液在紫外光與可見光的照射下裂解產生氫氣來測定，其產物組成將利用氣相層析儀(GC)分析。本研究在探討TiO2 與K2CO3 的莫爾比例及鍛燒時間對觸媒結構和特性的影響，並深入探討光觸媒活性與NiO 負載量的關係。由實驗結果得知TiO2/ K2CO3 莫爾比值為6 ，鍛燒24 小時，所得0.3wt% NiO/ K2Ti6O13 光觸媒在紫外光照射有最佳水裂解反應活性，產氫速率為87.2 μmol‧h-1gcat.-1，而0.3wt% NiO/ K2Ti6O13:Rh 在可見光照射下產氫速率為33.6μmol‧h-1gcat.-1。

關鍵字

六鈦酸鉀 ； 水裂解 ； 氫氣 ； 光觸媒

並列摘要

In this research, the photocatalysts K2TinO2n+1 are prepare by mixing K2CO3with TiO2 prepared by the so-gel method on the precursor at variable mole ratio, and are obtained by applying the solid state reacation method to calcinate respectively for 10 hour,24 hour and 50 hour. The photocatalysts prepared are then loaded with NiO on the carrier to obtain NiO/K2TinO2n+1. Finally, among these catalysts, those with the best potocatalyst activities for
producing hydrogen are chosen for doping with Rh ion. The characteristic of the photocatalysts are analyzed respectively by means of X-ray diffraction analyzer (XRD), UV-vis spectrum analyzer, scanning electronic microscopy (SEM) and the specific surface area analyzer (BET). From XRD results, it can be known that the crystalline structure of the catalyst is K2Ti6O13; besides from UV-vis it can be observed that the photocatalyst K2Ti6O13 which have been doped with Rh ions possess strong ability of absorbing light within the extent of visible light. From SEM resalts it can be seen that surface appearance of the catalysts are in the form of rectangular whiskers. In addition, from BET results, it can be known that the catalysts with molar ratio value of 6 and after being calinated for 24 hours possess the largest (specific) surface area. The activities of photocatalysts K2Ti6O13 are measured by using batch reactor with respectively pure water and 10% methanol aqueous solution under the irradiation of ultraviolet light and visible light for splitting to produce hydrogen, and the compositions of the products are analyzed by means of gas chromatograph (GC). This research is to study the effects of the molar proportion of TiO2 to K2CO3 and the calination time on the structures and characteristics of the catalysts. Besides, the relationship between the optimal quantities of loading NiO with the activities and physical characteristics of the photocatalysts are deeply investigated. From experimental results, it can be known that with the molar ratio value TiO2/K2CO3 of 6, after being calinated for 24 hours, the photocatalyst 0.3wt% NiO/K2Ti6O13 under the irradiation of ultraviolet light possess the best water splitting reaction activity, and the active hydrogen production rate of the photocatalyst is 87.2μmol/h, in addition, with the irradiation of visible light, the hydrogen production rate of the photocatalyst 0.3wt% NiO//K2Ti6O13 is 33.6 μmol/h.

並列關鍵字

water splitting ； hydrogen ； photocatalyst ； K2Ti6O13

參考文獻

論文，國立中央大學化學工程與材料工程研究所(2005)

【2】 G. Guoquing , K. Tetsuya ,Y. Akira“Reduction of carbon dioxide

on the photocatalytic production of hydrogen from water on mixed

metal oxides ” International Journal of Hydrogen Energy

【6】 Wen Yu Wang, Young Ku, “Development Status of Visible Light