近年來，金觸媒因在低溫下的高氧化活性而引起廣泛的重視，Au / TiO2是最受矚目的金觸媒之一。然而，作為此觸媒擔體的TiO2在實用上有機械強度差及表面積小的缺點，為了改善這些缺點，本研究以含浸法將TiO2塗佈於具高表面積的中孔分子篩SBA-15的表面，用此方法來提升TiO2的表面積並改善其機械強度，然後再用此複合擔體製備觸媒。
為了了解TiO2塗佈量的效應，本研究以重複含浸的方式增加複合擔體上的TiO2的含量，每次增加10 wt %，共製備出S15-Ti-10、S15-Ti-20及S15-Ti-30三個複合擔體，其中S15為SBA-15的縮寫，Ti為TiO2的縮寫，Ti後面的數字代表TiO2在觸媒中的百分含量。然後再用這些複合擔體以沉積沉澱法製出Au / S15-Ti-10、Au / S15-Ti-20及Au / S15-Ti-30觸媒，觸媒中的金含量皆固定為1 wt%。另再製備Au / TiO2及Au / SBA-15二個對照觸媒供比較分析用。
所合成的觸媒以粉末X-ray繞射（PXRD）、小角X-光繞射（SAXRD）、氮氣吸附（BET）、穿透式電子顯微鏡（TEM）、X-ray光電子能譜儀（XPS）、CO及O2化學程溫脫附（CO-TPD & O2-TPD）和感應耦合電漿原子放射光譜儀（ICP-AES）等儀器進行觸媒性質的鑑定。
觸媒的活性以CO的氧化測定，反應在常壓及25-125oC下進行，使用一個由玻璃做成的微反應器，反應氣體以連續流動的方式通過觸媒床，進料中CO的濃度為500 ppm，餘為空氣。另再於125oC下進行8小時的觸媒穩定性測試。
研究結果顯示，含浸法可成功的將TiO2的前驅物Ti(OCH(CH3)2)4送入SBA-15的孔洞，並於鍛燒後將之分解然後附著於SBA-15的孔壁，附著的TiO2為高度分散的非結晶物，其厚度隨重複含浸的次數而增加。附著的TiO2是以Ti-O-Ti化學鍵彼此結合，在TiO2與SBA-15的界面則是以Ti-O-Si鍵結合。複合擔體仍保有SBA-15的有序中孔結構，但孔體積及孔徑隨著TiO2附著量的增加而變小。複合擔體的表面積接近SBA-15而遠大於TiO2，其表面性質則隨著TiO2含量的增加逐漸接近TiO2，在附著量為30 wt %時則幾乎等同於TiO2。
觸媒的活性與穩定性皆隨金粒徑的縮小而上升，各觸媒的粒徑大小順序為Au / SBA-15 > Au / S15-Ti-10 > Au / S15-Ti-20 > Au / TiO2 > Au / S15-Ti-30。Au / S15-Ti-30上的金粒最小，換言之，使用複合擔體可製備出較傳統Au / TiO2更高活性及穩定性的觸媒。

The high oxidative activity of gold catalysts at low temperature has attracted many interests lately. Au / TiO2 is one of the catalysts with the most attention. However, this catalyst suffers from inadequate mechanical strength and low surface area due mostly to its support TiO2. In this study, an attempt was made to improve the situation by coating TiO2 onto the surface of SBA-15, a high surface area mesoporous molecular sieve, to create a new material, TiO2 / SBA-15, with a high TiO2 surface area and a sound mechanical strength. Gold catalysts were then prepared using this new material as support.
To understand the loading effects, TiO2 / SBA-15 of varied TiO2 contents, done by repeat impregnation, were prepared. Each impregnation increased the TiO2 by 10 wt %. Thus three supports, S15-Ti-10, S15-Ti-20 and S15-Ti-30, were obtained. In naming them, S15 designated for SBA-15, Ti for TiO2, and the number after Ti for the wt % of TiO2. The supports were then used to prepare Au / S15-Ti-10, Au / S15-Ti-20 and Au / S15-Ti-30, the gold catalysts, via deposition precipitation. Each catalyst was loaded with 1 wt % gold. Two other catalysts, Au / SBA-15 and Au/TiO2, were also prepared for comparison purpose.
The catalytic properties of the catalysts were characterized by powder X-ray diffraction (PXRD), small angle X-ray diffraction (SAXRD), N2 adsorption (BET and pore size), transmission electronic microscopy (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and temperature programmed desorption of CO and O2 (CO-TPD and O2-TPD).
The activity of the catalysts was investigated by CO oxidation at 1 atm and 25-125oC. The reaction system consisted a micro-reactor made of pyrex glass. The feed flew continuously through the catalyst bed. The concentration of CO in the feed was 100 ppm in air. The stability of the catalysts was tested at 120oC for 8 hours.
The results showed that the precursor of TiO2, Ti(OCH(CH3)2)4, could successfully be delivered inside the pores of SBA-15 where it decomposed upon calcination and then attached to the walls. The TiO2 appeared to be highly dispersed and amorphous. The thickness of the attached TiO2 layer increased with repeat impregnation. The TiO2 molecules were bound by Ti-O-Ti bonds, and Ti-O-Si bonds were formed on the interface of TiO2 and SBA-15. TiO2 / SBA-15 possessed ordered- mesoporous pores similar to those of SBA-15, but with smaller pore volume and pore diameter. The volume and diameter became even smaller with an increase in TiO2 loading. The surface area of TiO2 / SBA-15 neared that of SBA-15, which was significantly larger than that of TiO2. The surface properties of TiO2 / SBA-15 shifted toward those of TiO2 with an increased TiO2 loading, and nearly identical to those of TiO2 when the loading reached 30 wt %.
The activity and stability of the catalysts increased with a decrease in the size of gold particles. The size was in the order: Au/SBA-15 > Au / S15-Ti-10 > Au / S15-Ti-20 > Au / TiO2 > Au / S15-Ti-30。The size on Au / S15-Ti-30 was the smallest which meant catalysts with higher activity and stability than conventional Au / TiO2 could be prepared using TiO2/SBA-15 as a support.

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